I would be too. I'd be looking at some 32s probably. Maybe even 35 if I could handle the possible sluggishness. Pump 'em up hard and they're prolly not that sluggish tho. If the frame was made for 27" then you should have a fair amount of room to jam some big 700c tire meat in the rear triangle.
Chainstay clearance should be your biggest concern. I'm guessing no rear brake. Chainstay bridge would likely not be much concern. Even if it is you'll just have to let a little air out of your tire to get the rear wheel out. You got forward facing, horizontal dropouts? Or what?
Last edited by LesterOfPuppets; 06-10-11 at 01:19 AM.