There's a 45/2.8 Rokkor for the old Minolta LTM cameras, they *sometimes* can be had cheap, the last ones I bid on I lost for a lot of money. Performance wise I can't really speak of (haven't tried or seen anything)
Then there's the Rollei Sonnar 40/2.8, seems to be a very good lens but not easy to have cheap.
And also a very rare Olympus 40/2.8 (I think), which usually goes for an arm and a leg.
I was in the same position as you some months ago, and ended giving up and getting a M mount camera and a 40/2 Summicron
Say what?
Bulbous ?