There is nothing in the RV industry designed to accommodate that many people. Road crew coaches built for the entertainment industry come close, with Pullman-type bunks and travel coach seating, based on shells for 45-foot motorcoaches. With all that sleeping and seating space, other RV amenities (cooking, lounging) are minimal. And even there, with original costs on the order of $1,000,000 to $2,000,000 (depending on amenities, the shell costs more than $800,000) getting down to a $30,000 budget means something really, really old.
On the other hand, my family traveled for two months with four adults, six children age 2 to 15, in a station wagon hauling a nominal 16-foot travel trailer (but that was box length, and it had an bunk overhang over the tongue, so maybe a 20 footer by today's measures). It did mean on pair of adults fit into a dinette, two teens slept in pipe bunks, and four of the children shared a single queen bed. We had minimal kitchen and potty.
So anything is possible, if you can adjust your standard of living to what the space and budget provides.