15's easily, but some types of 14's (very very close). I myself run 15's

With a few additional mods to this successful combo, it is possible to mount 11 inch rotors and 4 spot alloy sumitomo calipers off a R32 skyline. (it works really well)

why dont you persue with the a series matched with the toyota sprinter 5 speed. there are two types to my knowledge, 2T & 3T. the later has a larger input shaft main bearing. the box is slim and is ideally suited to the tight transmission tunnel in the 1200's. Dellow eng in sydney makes a bellhousing to suit. I have found the gear ratios to be spot on.