Actually, from all the advice I've been given if you can nudge your GPAs above 3.0 and do well on the MCAT, you should have a shot at DO.
I had the same problem you did; I graduated with a 3.0. But I didn't want to risk a SMP so I took a heavy science content post bacc instead.
From my research into SMPs, as long as you get 505+ you're set for the DO ones, 510+ (or even higher) for the MD ones.