What bunkhouse should I look at?

We are in the same situation as you (2 adults and 4 kids). We have a Puma quad bunkhouse and like you, started wishing for more space. Just as we did, the kids reached the age where they wanted to start staying in a small, 2-person tent. Problem solved. If we had to do it over again, I'd make sure the bunkhouse had a separate slide for more room in that area. Like mentioned above, Puma has some very nice bunkhouse floor plans.