[quote="TwH"]
I liked your "d6 + wilderness level" idea, it's pretty clean, but it's still a hassle because wilderness monsters' "xp levels" don't map nicely to 6 wilderness levels, just try to map them and you'll see for yourself.
[/quote]
In Abstract Wilderness, I solved this problem by using a two-tiered system; one for individual XPV of the constituent monsters, and one for total XPV of the encounter.
Because while two dragons might have the same total XPV as 50 orcs (PS - I didn't look these numbers up and thery're probably wrong, you know what I mean), the encounters would play out very differently becuase of the different individual XPVs of creatures involved in the encounter.