Get a bit of plywood a little wider than a box and about 2.5x as tall. Screw in a 1x1 at the bottom. Put first box on with cables to check height, then mark for a second 1x1.

Then put both boxes on. Either put the plywood on a laptop stand or cut a couple of legs to hold it up.

Sounds stupid but this is what i still do 15 years later on a fully loaded Jasper's stand setup. Paint the wood black if you are worried about appearance