SmartWool Light Hikers
So I'd come at the problem from another direction: Namely, some sort of work-around. Let's discard the neoprene mocs, or for that matter trail runners that are designed to drain water after immersion. Both will stay too damp for your purposes. Teva sandalsor something like themshould be 80 percent dry one hour after immersion, by my calculations, provided you shake them thoroughly then hang them on your pack once you're back in hiking boots.
So then what? I'd get two pairs of good-quality wool hiking socks, one for your boots and another for under your sandals when you're in camp. SmartWool Light Hikers ($16; www.smartwool.com) would be fine. They'll soak up any excess water on the sandals, then help it evaporate, all while keeping your feet warm and dry. You won't even know the sandals are still damp.
That said, if the sandals are really soaked through, as in just out of the stream, then you'll probably need to add a Gore-Tex oversock to the mix (REI offers the Rocky Oversock for $50; www.rei.com). Put those over any ol' socks, and you'll have very dry and warm feet regardless of the moisture content in your shoes.
Hope that helps to keep things more comfortable!
For the best in river-ready kicks, read Outside's "Make a Splash" (July '04).