Sounds workable, you still have to scale treasure to the exp progression table, though.I think I have an acceptable solution.
The system I'm looking at (GLOG - rat on a stick edition) - proposes 1 xp per gp, and 200 xp to reach level 2.
So what I would do is that I would give XP per session, based on the rate of leveling up I want to see (say, 5 sessions) so 40 XP. A session where not much was done would have less XP - and a dead PC gets no XP, of course. There would be small bonus given in game for good role playing or great ideas.
I would *also* give XP for gold but at a reduced rate - say 10 or 20% of the 1 per 1 rate. This would still motivate the PCs to go get the treasure, but it wouldn't have such a big influence anymore. It seems best of both worlds.
Here's a thought: You could give exp for the challenges overcome/avoided (monsters, traps, puzzles), and for the /percentage/ of possible treasure recovered. (I know: gamist.)
So if the only treasure in the dungeon is a copper bowl worth 5 gp, and the party leaves with it intanct, full treasure XP. If the treasure is a 12-ton dragon horde and they only get away with 1 ton of it, 8.33% of the possible treasure XP. Thus the XP can be pegged to level while the treasure is pegged to the campaign norms and/or story.