Friend of mine bought a very nice but older class A for that price. Big slideout, diesel pusher. No over head bed but big couch and dinette to work with. It was about a 32-35 footer so would also look in that direction. I know there are a bunch on the local craigs list for close to what you have to spend.
A 28 ft C would be pretty claustrophobic for 6 when in motion and parked IMO. The only ones I can think of with bunk beds were jaycos from about 6 years ago and they will be more pricey than your budget and were in the 31-32 ft range.
I dont think builders build for families any more, most are set up for 2 with some thought to KIDS in the overhead bunk. Some super c's had nice sidewall bunks but those are very $$. Expand your CL search out to several areas and be prepared to travel to find a good one. the same friend went with other friends to LV to check out a "super clean" according to the seller A and it turned out to be anything but!
Lotsa luck, BTW most of the C's in your price range are early 2000's and older and many did not have slides then.