A crashed track bike isn't a bad choice if you get a great deal. A scratch in the paint on the frame causes a total, and the bike may be fine. The steering stop is the on part to really check if a bike has been down on the track. Or anywhere else, for that matter.
If the bike has aftermarket clipons and aftermarket rearsets, chances are it's been a fairly serious track bike. Meaning it's probably been on the ground. But, they crash as well as any bike, and as long as the frame is straight, a crash only means the price is lower.
That's my post crash (uh, never mind how many) wisdom.