I saw an add for this new disposable ice chest that is supposed to be an alternative to styrofoam. Looks an awful lot like the swarm traps you can buy, but better suited for some top bars and cheaper
Like the swarm traps you can buy the volume is about comparable to a nuc, but I suppose you could connect 2 together if you want a large trap.
Can only buy from REI right now, but price is only $10 so pretty cheap. I am tempted to get one, rub the inside with bees wax, and then see if I can fit an old comb from my top bar hive in there and add some lemon grass or an attractant. Of course if I did the same with some plastic pots it can work too. Location, location location.
I just figured it looked like similar material to the commercial trap but cheaper and a more convenient shape.