I once heard that road rims aren't strong enough to deal with the force of v-brakes, is this true? What about your standard cantilever brakes?
Not true--the pad/rim contact force should be more or less independent of the brake design (assuming the pad/rim friction coefficients are about the same, as they will be if the pads are of similar material).
V-brakes tend to require more cable pull to actuate than other types, which does make them incompatible with road brake levers. No problem with the wheels, though.
If the brake pads are worn down to the metal, then yes they can make a screeching noise and eat into the wheel. This will eventually destroy the wheel by creating a bow shaped groove in the wheel, whereby the it will become deeper and deeper until the inner tube pops out from the top and pops on the metal brake block. Of course that's an extreme situation of bike negligence. In answer to your question, under certain "extreme" situations it could happen, however this shouldn't hamper your choice between cantilever or v-brakes, just change your brake blocks and other than light wear and tear (over years) your rims should be absolutely fine.