I'm afraid I just created a new thread that was meant as a reply for this one -- too late at night I suppose
It asks about the use of Sprint Extended ROM with Saridnour's 3.5 ROM.
Fortunately it may be of interest for other new 3.5 ROM users, and I edited it to be more general. Please take a look:
http://ppcgeeks.com/viewtopic,p,30640.html#30640
With apologies.