At some point I plan to build up a touring bike, and already have the stuff for my rear wheel: Ritchey OCR 36-hole asymmetrical rim, which has a bit wider profile than standard road rims.
For the front I've been planning to use a Sun CR18, a double-wall, single-eyeletted rim with a good reputation for durability and a similar width to the Ritchey I'll be using on the rear.
Here's the deal though: I've got a bunch of 32-hole front hubs sitting around, and would prefer to use one of them instead of buying a 36-hole (which are harder to find, esp. for good deals).
I suspect a 32-spoke front wheel would be fine for touring if it's well-built and uses a solid rim like the CR18. I build good wheels, and front rims undergo significantly less stress than rear wheels because
a) there's no torque transmitted from hub to rim by the spokes
b) the wheel is evenly dished so spokes on both sides have equal tension