How many races are 'draft legal'? And what does that mean for the bike setup I need?
If I am in the market for a new bike, should I go for a pure TT setup or some hybrid setup that
will work both for TT and draft legal races?
I may be completely incorrect in saying this, but I know around Indianapolis, there are no draft legal races, and I am sure that there are few of them until you get to the pro elite level. As far as drafting, I think you'd just get the same TT style bike, as I don't think you'll actually see a peloton working together on a tri (or shouldn't see it, as they are individual races).
You won't see many draft-legal tris for the "public". And the bike restrictions are different. Basically, for a draft-legal, you'd be using a slightly aggressive road set-up with shortie aero bars. Not a tri set up at all. Now if you have a UCI TT set-up, then your seat position will be okay for ITU-style draft racing (seat 5 cm behind the BB spindle -- USAT rules for non-draft allow for 5 cm IN FRONT of the BB spindle).