275 has been done without flares...
The Meaty Tire Thread - NASIOC
You may want to dig through Horse's history to get more details. That thread is also a very good wealth of various meaty set-ups.
If you want a deep wheel you will have to sacrifice offset. A lower offset just means that you will need more camber to keep the tire in the fender. Roughly, 1 degree of camber amounts to about 5mm or tire movement towards or away from the fender or strut, or 5mm in offset. Once you figure out how far away the hub mounting surface is from the fender and the strut, it is pretty easy to do the math to figure what will fit and what kind of alignment you'll need.