Most any small ones (i.e. with four axles) will make that -- I have RS-1 and RS-2's that can do that, and F3A's. It's right at the limit of my VO-1000 (depending upon how accurate my measurement was!) -- some locos can cope with a slight tightening for a short time, but not 90 degrees of it. The limiting factor seems to be how much rotation you can get out of the trucks... if you place the loco upside down and rotate each truck the opposite way (as if going round a tight corner), the perpendiculars from the trucks will meet at the centre of the tightest circle. You'll want to be wider radius than this extreme -- on the VO-1000 it's about 6.5-7".
Any smaller loco should be fine -- Kato critters and Plymouths etc...
