Mavic X719 in 29″ which would be more than fine. I have never tried the touring rims like the Mavic A119, A319 or A 719 as they take tyres up 47mm width. Alternatively Rigida make some lower cost rims like the Sputnik that should work if you intend to get wheels built. I am no going to mention Stans rims as that has already been said. Spoke count will depnd on rider weight. 32/36 should be pretty bombproof with Sampin Race spokes. As for hubs Shimano MTB hubs should work well.
However why bother getting a set built when Campag make the excellent Khamsin CX wheels Sciroco and Vento CX wheels. All these are good and the Kamsin start at around £130 for the pair. Campag wheels I can supply as does practically everybody else and custom build wheels I also do but would be more expensive than a pair of Khamsins.
As for tyres I would look at Conti or Vittoria personally.