I've had this exact same thought, though I'm not in a position to follow through with it.
Here are a couple of articles on twin-charged setups. Neither use a rear mount, but the articles should give some ideas as to how you can do the setup.

The first is a twin-charged C32, though it is not a compound boost setup. The supercharger is turned off at high RPMs:

Autospeed - Insane!

Here's the article on the Ford Mustang Hellraiser. It uses compound boost:

Ford Mustang Turbo Kits - Hellion 1,000 HP Bolt-On Turbo Systems - Hot Rod Magazine

One thing to remember about compound boost is that the pressure ratios are multiplied rather than added.

If you decide to go this route, please keep us all informed.