Is it safe to enlarge the wheel stud holes on Iron drums (or aluminum for that matter)? I just change my rear axles out and I now have larger 1/2" studs and the drums won't fit anymore. I actually have ONE alum. drum in my "inventory" that fit, but the other alum. drum didn't, I guess I pulled them off two different cars.

I would probably have the Machine Shop boss at school enlarge them if it is safe, he's a friend of mine.

I'd really rather not buy new drums, but if I must, does anyone know of a drum with the stock 5 x4.75" bolt pattern but larger wheel stud holes?

Sure, not a problem. Just ream the drum holes up to 33/64".
The axle hub is what really locates the drum.