Your question deals with several issues and I need to give you my approach to them. As you mention, man was made in the image and likeness of God (Genesis 1:26-27). As is often the case, my take on this is a bit different from that of others. Image as a word deals with form or basic structure. Likeness deals with general similarities (or "similitude" as in James 3:9). Therefore, I take these words to have a slightly different emphasis. The image of God I take to be His basic structure. Since God is a three-in-one being, I believe that He made man into a three-in-one being. This full image was lost in the fall of man because man's spirit died and can only be fully restored in salvation when the spirit of man is quickened. The three-in-one connotation of the image of God is furthered supported by the plural pronouns used in the announcement - "Let us make man in our image, after our likeness" (Genesis 1:26).
The likeness of God deals more with the moral nature of man. He has a sense of right and wrong, the ability to reason, to love, to be merciful, and so on. He was made like God in his moral nature--though most of this nature was lost at the fall.
Next, we need to consider the spiritual nature of God. As you know, John 4:24 states, "God is a Spirit: and they that worship him must worship him in spirit and in truth." Jesus said this in response to the Samaritan woman who was getting worked up over the correct physical location for worshipping God. In other words, God is not to be thought of in physical terms but is to be worshipped spiritually as a Spirit. This, to me, points to the greatest danger in thinking of God in terms of having a human-like body of any sort. Even God the Son became a man. His manhood is distinct from His deity. But there is more.
Isaiah 40:18 asks, "To whom then will ye liken God? or what likeness will ye compare unto him?" This is in the context of the sin of making idols of God in any form. God is not to be conceived of as having a likeness understandable to man. The Lord pointed out to the Israelites that when He appeared to them they "saw no manner of similitude on the day that the LORD spake unto you in Horeb out of the midst of the fire: Lest ye corrupt yourselves, and make you a graven image, the similitude of any figure, the likeness of male or female" (Deuteronomy 4:15-16). That is, God did not appear to them in any form; therefore, they are not to think of Him in any form--even in human form, either male of female.
Romans 1:23 states that depraved men "changed the glory of the uncorruptible God into an image made like to corruptible man, and to birds, and fourfooted beasts, and creeping things." Some may think that this only has to do with physical idols that are worshipped. However, images come from the imaginations of the heart. We are not to imagine (or put into an image) the glory of God in the form of a man. That is the importance of understanding that God is a Spirit and not a body--physical or spiritual.
Others have pointed out to me that the scriptures speak of God having hands, arms, eyes, etc. However, He also has wings (something that would not fit into the image of a man). We can understand these as metaphorical uses; they refer to God doing the things that would be done with hands, arms, wings, etc. This is not changing scripture. God is also a shield, a lion, and a strong tower. We do not insist on Him morphing into these things literally. God uses metaphors because that is how human speech describes things.
Isaiah 31:3 states, "Now the Egyptians are men, and not God; and their horses flesh, and not spirit. When the LORD shall stretch out his hand, both he that helpeth shall fall, and he that is holpen shall fall down, and they all shall fail together." Men and horses as flesh are contrasted to God as spirit. Other scriptures also contrast flesh and spirit (Matthew 26:41; Luke 24:39; John 3:6; 6:63). In order to understand the importance of understanding God as a Spirit (John 4:24), I have come up with a short list of distinctions between the two.
- Flesh is visible; but spirit is invisible--as is God (Colossians 1:15; 1 Timothy 1:17; 6:16; Hebrews 11:27).
- Flesh as matter takes up space and has weight; but spirit is not matter and is incorporeal (Isaiah 31:3; Luke 24:39).
- Flesh is corruptible; but spirit is incorruptible (1 Corinthians 15:50).
- Flesh is temporal and time-limited; but spirit is eternal (2 Corinthians 4:18).
- Flesh is weak (Matthew 26:41); but spirit is powerful (Luke 4:14; Romans 15:19; 1 Corinthians 2:4; 5:4).
Now I realize that flesh often, though not always, refers to the depraved nature of man and not simply to the physical body. However, it is in the form of the physical body alone that we are so warned against identifying with God (as in Deuteronomy 4:12-16; Romans 1:23). Against this physical concept of God, Jesus emphasized that He is a Spirit (John 4:24). The danger is clear. To conceive of God as having a body leads eventually to idolatry. To think of Him in such a way is to think of Him wrongly.
I think that one of our problems in thinking of God as Spirit comes from our ignorance of that which is spirit. Since we cannot see it or touch it, we somehow think of it as being less real than matter. However, the truth is the opposite of this conception. Spirit is eternal, incorruptible, and powerful. A spirit can move from one place to another and therefore has location. A spirit can think and act. Spirit is more real than flesh. This is a bit of speculation, but I think of the spiritual world as another dimension co-existing with and beyond the physical world. Elisha prayed so that God would show his servant the spiritual army protecting them at Dothan (2 Kings 6:17).
It is likely that spirits can touch in the spiritual world. An angel touched Elijah in this world (1 Kings 19:5). I suspect that they are as real to each other as we are to each other. Though their substance is not naturally detected in our world, that does not mean that they are spooks to each other. They meet with God in counsel, take messages to earth, and fight the evil spirits (Daniel 10:13, 20). We certainly understand next to nothing about this world, but it is not a world lacking a sense of reality to its inhabitants.
Now, did Christ have an eternal body? I know that He appeared in human forms before His incarnation, but angels who are spirits also do this. I think that the Bible clearly teaches that He took on a body at the time of the incarnation. It was prepared for Him (Hebrews 10:5) so that He became flesh (John 1:14). The warning of thinking of God as having a body would apply here. I think I see where you are coming from with Jesus being the image of God and man being made in the image of God. However, God said He would make man in "our image." It is the combined image of God into which man was created; a three-in-one being. Jesus is the image of God for "in him dwelleth all the fulness of the Godhead bodily" (Colossians 2:9). It is through the Son that we know the Father (Matthew 11:27; John 14:5-10). He became flesh so that we might identify with Him, but we must keep His humanity distinct from His deity in our understanding.
I keep going back and adding more. I do not claim to have any depth of knowledge concerning the essence of God or of the spirit world. Our knowledge of Him and His world is certainly minuscule. However, I know that we are warned against thinking of Him as having a form (including human) and told specifically that He is a Spirit. I think we should be obedient to this Biblical warning in our teaching.