Jeremy,
Here's what Rob at Psimet recommended for me:
Front=White Ind. H2 F Silver (or black +$10) hub laced to a Kinlin XR-270 rim 20f/RadialX using CXRay-Black spokes and DT-12mm-Brass-Silver nipples

Rear=White Ind. H3 R Silver (or black +$10) hub with Shimano freehub body laced to a Kinlin XR-270 rim 24r/2X using CXRay-Black spokes on the Drive Side and laced 2X using CXRay-Black spokes on the Non-Drive Side and DT-12mm-Brass-Silver nipples

Estimated weight should be in the neighborhood of ~1456g for the set and the quoted price is $599

These sound like what you're planning to build for yourself. Talked to my bike shop owner to see if he'd be interested in building some wheels for me, and he said to be honest, they wouldn't feel comfortable building anything with less than say 28/32 spokes, just because they're not expert wheelbuilders. I'm going to do a little more reading, but I think these may be just the right thing. I assume I can get these in a configuration that works with Sram, but that'll be my next question.