Yeah, it would be noodly if they stick to normal rims, but like Rolf, they build the rims to cope with this, and people always seemed to be surprised when it actually work.
eBay alert setup... The only problem I imagine is when the rim wears it's going to be impossible to find a replacement. So it's a single use wheel really.
^ these are those funky Shimano wheels, disc+rim brake, 16 spokes, nipples in the hub. Forgot the model but they're mad and I want some.
Edit: Shimano WH-M575?
they don't all have 6-bolt disc fitting apparently. So cool