Specialized Stumpjumper 650b front, 26" rear?

I've got an '01 stumpjumper frame for free from a friend. I've been riding an undersized mtb frame (26" wheels) for quite some time.

The problem that lies with the Stumpjumper build is my fork swap over, I have a Dart 3 on my old bike, the thing feels like an anchor when I'm riding.

I was thinking about getting a 650b velocity blunt and a rigid fork for the front. This shouldn't muck up the HT angle all that much.

What are people's opinions on this?

Please don't tell me to run out and buy a 29er since I can't afford a new bike at the moment. I thought the 650b/26er set up would be alright for rolling, and not screwing up the geometry.