I wasn't going to post anything in this thread but I think some of us are missing the point of what Paul said and it's relationship to the time he was living in. I believe it has more to do with custom more than any specific or literal length of hair. I know the common perception is of a Jesus with long flowing hair, would Paul have condemned Jesus? Would the other apostles allowed it if he was? I believe it has more to do with offending others, the sheep still in need of milk. Let us look at it spiritually instead of as carnal "rules" of dress code.
We should not project ourselves as radical in style or dress or manner, nor should we be perceived as someone who flouts custom or decorum in regard to how we appear, what we eat, etc. What is the point of offending a brother or sister and then expect them to seriously ponder our beliefs.
I must admit I see someone with a shaved head on one side of his head and long hair on the other side, pierced nose, ears, tongue & naval, tattoos all over the body, I tend to think this person may not have much to offer me in regard to reason, carnal or spiritual. This may be an extreme example but I think you get my point.
This points to anything that may offend others but is not really critical to our salvation, it is not that we water down the Word or compromise our beliefs in regard to our Lord but why would we present ourselves as an antagonist, we will repel some that we may have reached otherwise.
1Co 8:13 Wherefore, if meat make my brother to offend, I will eat no flesh while the world standeth, lest I make my brother to offend.
Joe