Rent a server. Play conquest or rush on it. Wait for it to get full. Change to cq dom. Maybe you have a 24 player cq dom server for a while (until there are less than 17 players).
Happened to me when I changed our server from rush to cq dom. Lasted for 4 or so rounds.
I've played some 12v12 and it was pretty fun. The extra people didn't really seem to mess up the spawns as much as I would've thought, but there were a few instances where someone would spawn behind or in front of me. Can't imagine 32v32 though!