But yeah, you could really use any tray or saucer as long as the are elevated and you're willing to do some modifications. Get the pump box with the built-in floater switch bilge pump, run some pvc, drills holes in it, attach silicone tubing to whatever the tray is, seal with silicone. Then you run a hose from the box to a drain. It's pretty simple, and makes life much, much easier. I basically copied BK's Bucket Company drain box, but this was a lot cheaper.
Really you don't even need the box. Just the bilge pump with the built in floater switch. You could use a regular bucket or a plastic bin. The box I have just makes it easy because the fittings are 3/4" and you don't have to install bulkheads or anything. You do have to drill out the plastic at the end of the box's fitting though.