I know this is an ancient thread but I'm digging it up just to respond. I finished my bike last year. It runs fine and I've taken it around a few times. I've never been pulled over or stopped by a cop
When I first built my bike I did a search on TN laws and I'm fairly certain it complies with them except for the 50cc part. It's 66cc but the only way you'd really know is by taking the whole motor apart and I've not even done that myself. I'll have to do some digging around to refresh my memory on the laws but I know I researched it thoroughly at the time.
I wrecked my bike one time on the way home from work due to a faulty (weak) front fender. Luckily there weren't cars racing all around me. I can't stress how important it is that you get high quality fenders (if you want them at all) and secure those suckers! Don't let them rattle around at all. Use some kinda rubber stripping to dampen the vibration and watch for cracking along where the connections are.
Here's a picture of my bike at about 95% complete.
Sorry I didn't see these posts so long ago. lol