You could totally convert the Quicksand to a monoblock, and I would encourage the project!
The big issue with doing so is that you need to feed the amp with a differential signal to drive both channels. You could convert a Quickie to do duty in this position, which would involve using the hardware and tubes, but setting up the second half of a cathodyne phase inverter and sending that to the Quicksand.
Inside the actual Quicksand, you could decrease the inductance at the output and remove the output coupling caps. If you do this, I would strongly recommend removing the ground posts on the speaker outputs, you don't want to forget that you have removed the DC blocking from the outputs of the Quicksand, only to provide an 8 Ohm path to ground later on.
You could also build the second Quicksand into the first.
If you're handy with perf board, you could also make a basic differential phase inverter out of maybe 6 mosfets.
-PB
(PS - we are here to support wacky stuff like this!)
