I know someone with a class C, and they loved it. Because of weekly street sweeping, they had to move it twice a week, and also took it to every soccer game to have their own bathroom!
I like my class A, as most have enough GVWR to have extra cargo rating, and I have automatic jacks and the ability to tow my 4,200 pound Ford Edge. Many class C's are very close in curb weight to the GVWR, and can not carry to much cargo. That is why I upgraded from a 1985 class C that could not tow anything to a new 1997 class C with a 5,000 pound tow rating. It also had much better cooling system, and larger engine.
Good luck with your search. I think you will find that many class A's don't sleep more than about 4-5 people (mine sleeps 6 standard, but with the dinette delete option I picked, only sleeps 4). My buddy's class A Country Coach only sleeps 2 in the rear queen bed, he likes it that way, but when I went along as the driver, I had to sleep in his recliner, and did not like it much at all. . .
Many class C's will sleep say 6 - 8 (I have seen them sleep as many as 10) but only have seat belts for about 4-6. My buddy's class C only had a 1,200 pound cargo rating (including water, food, camping gear and people!) This did not work well with his 5,000 pound cargo trailer and it's 500 pound hitch weight and the two teens at 160# each, that along with his wife and his weight, 50 gallons of water (alone is 400#) was WAY over the GVWR of the motorhome.
Only the "Super C" built on the GMC 5500 series truck chassis had a decent GVWR of 19,000 pounds. Yet GMC stopped building the 5500 series trucks and the 8.1L engines in 2007. It was not much later that GMC stopped making motorhome chassis too. . . You can buy a new F-550 based pickup class C, with a decent cargo rating and 19,500 GVWR. You can get the F-550 with either the powerful 6.8L V10 or equally powerful (but heavier) 6.7L Turbodiesel. You can get 4X4 or 2 wheel drive as well.
Good luck!
Fred.