Hi James,
A few questions;
1) How high do you need the waders? Do you plan on going hip deep?
2) What about just taking your dive booties, a decent pair should keep your feet and ankles warm, if not dry or dryer. Ware with a pair of warm shorts and with all the bending and working the pan your legs should stay warm, or at least OK. Bundle up on top and it would help a lot.
3) Cheapest option I can think of it two HD trash bags and some duct tape to keep them tight. Just wrap the extra around your leg and secure with some tape. Cut the tape to remove and you can use them again. One thing though, if the water is mountain fed, as in snow or glaciers, it is going to be between 35 and 40 degrees, you don't want to stand in that kind of water for a long time, you legs will go numb! I know! smile

I have only paned a few times, but I don't remember getting that wet, we mostly just got the sand from the edge of the river. Although I do remember one guy who had a gas pump, metal trough and a bunch of other stuff, he stood in the middle of the diver (Low and slow) and filled a wheelbarrow full of muck for the trough. But this was not a camping set up!

Also on the Wiggy's Light Weight Waders; "They are made from 200 denier coated oxford nylon upper and a rubberized sole with all seams taped." I think that was one of your original options.

Wolfman