[JFreak]

It seems the only reasonable solution costs a little money.

What you need is two expansion chassis, one with HD|Accel and another with HD|Native. Then set up a dual-boot system drive (two partitions, two separate installs, one with PT10 and another with PT11).

And naturally, you swap expansion chassis cable before you re-boot to another system. That is the only way to be able to use both in same Mac Pro.

That said;

I would strongly suggest that instead what I just said, buy a new top-of-the-line and fully loaded MBP + HD|Native Thunderbolt. Doesn't cost any more than the expansion chassis route but gives you another separate system (that you can put out of sight easily). You only need to swap the DigiLink cable from the native box to the Mac Pro when you swap systems.