If you can find one, I would recommend the Group Industries 1928 TSMG. I saw one for the first time several months ago, it was at a show and I believe was recently at Knob Creek as well.
It had a M1 grip frame and a ring front sight(over a threaded plain barrel) and a M1 late style rear sight.
I changed out the grip frame for a GI 1928 frame and put on a GI compensator.
The gun will make a great shooter and the M1 rear sight I think is more useable than the original 28 sight(i got one of those while the getting was good, but I don't have any immediate plans to install it; apparantly there are examples of the military using the later M1 protected sight on 1928s.
anyway, I am not sure how many are out there, but I am real pleased with this one. The receiver is great quality and I think it is more interesting than a West Hurley.