Here is the goal-To be able to use my amp/rack as a setup and use my laptop as another setup and be able to A/B/Both between them.

I was thinking I could split my guitar cable and run one to my amp and the other to the in on my Mbox. The amp would run to the cab as normal. The 1/4 out of the Mbox would run to the cab or the house.

Is this possible? Or would I need to put the Mbox out into a poweramp before it goes to the cab/house?
well, the mbox would need to run through a power amp at some point. that means if you are running to the house pa, then they would have a power amp there. however, if you run straight to a cab you would need a power amp. you cant push the speakers with just the small signal from your mbox and computer.
Thats what I figured, I just wanted to make sure it was possible without blowing anything up, haha. Thanks!