Lanefan
Victoria Rules
Another, perhaps more out-there, option might be to try basing xp rewards on degree of individual risk taken, in whatever situations may occur.How do you quantify those steps is the trouble I am having with that, I guess. It feels arbitrary, and I am looking for something procedural and concrete.
So, for a combat where the fighter stands in and gets her face pounded while the wizard sits back and safely casts spells, the fighter gets more xp than the wizard. Where the thief takes risk disarming a trap, only the thief gets xp. Where the whole group is at about equal risk, equal xp for all.
The specific intent here is to encourage risk-taking - quite literally making the game a high-risk high-reward proposition.
A corollary here might be that you have to go 1e and vary the advancement charts by class if you find in general that some classes (e.g. Clerics) simply don't get exposed to as much risk as others.