Is it possible to use some sort of valve to divert all of the exhaust through one side of the divided exhaust housing (up to a certain rpm) for faster spool, and then open it up to both sides for high rpm power?

 

How about some creative exhaust plumbing, a eletric cut out, MSD RPM activated switch and some relays.
Is that a good place to start?
Or insted of a RPM switch how about a pressure activated switch?
I don't know on any one that makes what your asking for so it sounds like you need to make it hapen on your own.

 

All that would do is cause a restriction at the turbo and slow spool time. Creative thinking trying to accelerate the airmass to hit the turbine harder. Easiest way to fast spool time is short and unobstructed connections from the exhaust ports to the turbine and a free flowing exhaust system behind the turbo...

BTW, were you at SLP day?