Would it be feasible to use floor pillows or bean bag chairs instead of desks?

Actually, the stadium seating is not a bad idea. I have 3 steps in my room, that go across the length of the room (think sunken living room.) The building was designed in the 70's! ha ha!

Anyway, it is IDEAL for teaching. The kids sit on the steps and I sit in front of them. If you could get risers, the kids could sit, and then put their legs in front of them.

 

That is a lot of students! I have a handful of pillows & beanbags (but use them as rewards). You can also get carpet squares which are a little easier to stack. I also have a crate of clipboards students can grab whenever. At my old job I had 4th & 5th graders sitting on the floor/ carpet & it didn't seem to be an issue. I did feel though that without desks/ tables classroom management was a bit trickier. You also can get those plastic/ wooden folding tables. I actually use those in my gen music room b-c I don't have enough desks. Target has ones for $15 that fit 2 students.