I've just picked up an S-Works Stumpy and so far I can only think of one word to describe it. FAST!!! My only concern are the wheels. The bike comes with Roval Control XC Race wheels which use DT Swiss hubs with a 24mm aluminum Roval rim. I believe that the spokes are DT Swiss Revolutions (2.0X1.5X2.0mm) but I'm not positive so I've sent an email to Specialized to find out. Wheels have 28 spokes in the rear and 24 in the front. These wheels are great but I'm a big guy (230-235lbs) and I'm worried that the wheels may be a bit flexy.

If I'm right about the spokes would it make sense to rebuild these wheels? Am I right to worry about flex or failure? If so any recommendations on a spoke choice?

Thanks,
Mike

Umm... ride those wheels till they fail. Then replace them with a 32h front, 36h rear set.

Have them checked to make sure they have been properly tensioned and that is at the highest the rim manufacturer recommends for that rim. That is what is most important to assure strength and longevity if a wheel.

I understand your concern and I'd be a bit hesitant about where and how to ride those wheels too.
If it was me I'd put some nice narrow slicks and a road cassette on those wheels and keep them for road use, or maybe some moderately skinny semi-slicks for light singletracks/gravel roads.
Then I'd do as Tabor suggests and get some with a higher spoke count for the really rugged backcountry riding, maybe even get a 48H rear built up for the ultimate in carefree riding.