Class A Coach with 4 proper seats w/ seatbelts?

From 2007 to 2010 or 11 Newmar offered a model much as you're looking for, the Allstar line. Check their brochure archives for those model years and look at the models 4154, 3959 and 3951, both have permenant sleeping arrangements for 4, and offered permenant seating for 4 in captains chairs. Not sure of your budget, but these would probably work for you.
Bruce