I've never ridden anything less than, or more than, 36 spokes. At my heaviest I was just over 300. The only problem I ever had was back in the late '80s with a pair of relatively inexpensive stock tubular rims with a tendency to break spokes when I'd hammer up a hill, even though my weight was down to 212 at the time. Those were ditched pronto for a set of then-high performance clinchers that a good friend built for me. I don't recall the exact specs, but they were Mavics with 36 spokes, X3 or X4, I don't remember which. I never had a problem with them of any kind.
I guess my point is that it depends on the wheel, and the care taken in its build. I would think any decent after-market or custom wheelset with 36 spokes and a X4 pattern would stand up fine. It's OEM wheelsets that I don't trust, but even then only those that come on mid-price (or cheaper) bikes. Also, pay attention to how you ride. Try to ride "light" if you can - avoid being dead weight on the saddle when you see a road hazard coming up. Shift your weight onto the pedals so you at least get a little better distribution of the load between the two wheels.