You can build a rear wheel with 32 or 36 spokes that is still fairly lightweight..
I had a 36 hole Velocity Aerohead built up on Campy Hub with Straight gauge dt spokes that came in right at 950grams..
If you consider using your current hub I would look at using the DT Swiss RR 1.2 / RR585 rim.. 30mm Deep Rim, very solid rim to build up..