I've got 255/50x17 Nitto 555 G2, on the back of my 57sd (actually, on the back of one of my 55s at the moment). (Supposedly) "ultra" high performance, 27"+ tall. Nitto makes several uhp 17" tires, 26+ tall, so they don't look like rubber bands.
that's the size (255/50R17) I used on my old 5th ave back in the day and am leaning towards on my duster after the big bolt/disc brake conversion.....235/55R17 is a fairly common size (standard tire size on mid '00 mustangs, IIRC)