Kai, this is really nice work. very simple and easy. With a little modification, it can be made to clean Cornies too.
Assuming a 1/2 FIP pump outlet, you could use a 1/2 MIP x 1/2 barbed fitting with the pvc tube epoxied onto the barb for the carboy cleaner.
Make the hole in the bucket lid a few inches smaller than the corny ... say a 7" diameter ... so that the rubber top of the corny will sit on the bucket lid. Make up a line with a 1/2 MIP x 1/4 barb, a couple feet of vinyl tubing, and a black liquid QD. screw the mip fitting into the pump, snap the QD on the corny liquid out, invert the corny and turn it on.