Mirror to a Mac Mini
 

Right now I SuperDuper my MacBook Pro to a USB disk drive. Full bootable image.

I'm thinking about buying a new gen mini. Can I mirror my MBP to the mini periodically to use it as a full running hot back up?

Unlikely: I'm guessing the new mini will have a special OS build, and won't boot from what you have on the MBP until the OS has "synced up".

For what its worth, I had a Mac Mini (Core Duo from a couple years ago) running 10.5.6, backed it up to a USB hard drive, installed a new blank 320gb 7200RPM drive in a new Mac Mini (2009) booted the new Mini to the USB drive, and restored my OS.

The new Minis ship with a 10.5.6 DVD. Just remember to use the Applications disc to upgrade the iLife on your new Mini!

10.5.6 doesn't only come in one flavor, though. It's usually best to be careful...