I hope money wwill have ALMOST no weight, let's say 1 goldcoin = 0,0001 weight, so if I'm carrying 1000 gold = 1 weight.
Further on: interchange with traders: let's say 1 Ruby weight 0,1 and has a value of 10 000 goldcoins or something.
Just an idea I like, nothing more.
If not like this, do it like in DD = money has no weight. And like Destello said: give players who play hardest difficulty other loot to find ! (so it give indeed more satifaction playing (in) a nightmare