I've been reading on the 4th Edition trying to get a basis for a system which will allow DM's to choose between using 2nd, BCRS or 4th Edition rules for their domain level campaigns.

I reached the conclusion that Birthright should be completely independent of the edition at the domain level. Thoughts?

To make a system like that work, we'd have 3 basic solutions:

A) Players choose a style of play (law/guild/temple/source), which they collect full regency for that type of holding in addition to if they control the province.

B) We go with a skill system like the variant rules on RP collection in BCRS, where a multiclass character with a good selection of skills can gain RP from several styles of play.

C) Setup the noble class as the only class that can draw RP, forcing players to devote a portion of their personal power to domain management. ***I'm not sure how non-casters would collect from source or if allowed, just fleshing out my thinking right now

In the end it would probably be a certain combination of these things, but I presume that D&D will always have levels (because it's a way of measuring a player's powers/achievement/advancement & young people like that) & there will always be abilities (aka skills) under one guise or another.

From that point we simply have the players make an arbitrary decision on how they will advance their domains & you can have birthright in any flavor you want it.