I am the original purchaser of a TREK 720 Frame that has hung in my dry basement since it was purchased in 1985, and never been completed. I'm not a bicycle mechanic, Brit Motorcycles are my passion, but I do enjoy riding a bike with the geometry of a touring bike. I bought the bike from a dealer in Lake Forest that got stuck with it after they ordered it for another client. The serial number leads me to believe it is a 1984 frame.
It has never been completed. The only component installed on it is a Bernard Hinault, who else, autographed series roller bearing set for the front fork. That set is also marked STRONGLIGHT.
You'll have to excuse my inaccuracies in a description, but here are a couple of dimensions. From the center line of the opening for the crank to the top of the seat post is 58 CM. From the center of the opening for the crank to the REAR of the chain stay is 50 CM. The serial number is 143985.
As I said, I am not trying to sell this via this group, only let the group know that the frame will be on eBay this Sunday, July 29th. If you want to see the photos I have taken, go do a search for the seller named danbike.
Dan