Where can I find a reasonably priced very large hard case?

I’m looking about for a large hard case for an RC helicopter—the helicopter is heavily modified to take a camera, so a normal RC helicopter case isn’t going to fit.

The overall dimensions of the heli are 24” long, 24” tall, and 12” wide. I’ve been searching around my usual places for hard cases, but I’m not finding anything this big (most stuff is topping out at carry-on luggage size of 22“x14“x9”).

Any idea where I can find a hard-sized case that’s roughly 28“x28“x14”? My plan B is to build it myself, but would rather just find something online if I can.