A few suggestions.
1) You can very easily keep track of exactly what events a player plays on. If you have someone who will spend the time to reliably put in how each team finishes at each event, it's trivial for the system to "rank" players using whatever criteria you want - including only counting points from previous seasons (i.e. you never move up mid season, because only your point total as of Jan 1 counts for the next year.)
2) The system does not do well with information it doesn't have - which means it isn't going to do you any good unless many leagues are using it. So the first part is making it as EASY and as INEXPENSIVE as possible for leagues to use it. Even then, you still need to have people checking photo ID on the field (whether it's palyer ID, which oyu need photo ID to get, or just government photo ID as it currently is in PSP), a SIGNIFICANT portion of the time - a player should have a reasonable expectation of getting checked at least once at a tournament. How are you going to make sure legues are doing this? Is the EPA going to volunteer staff to do it?
Honestly, I'd offer the ID system to other leagues for the sake of giving them the ability to know which of their players are playing Millenium, but I wouldn't try and count local event experience in Millenium rankings.
Why?
Because all you have to do to artificially deflate your ranking is not play non-Millenium events, or at least not non-millenium events who use the ID system. And if you're giving the players a reason to avoid the ID system, then you're giving the promoters a reason to avoid the ID system.
You don't want to push people up for paying. You want to push them up for winning (at the level you're considering, winning a local event shouldn't mean jack **** in regards to what your millenium ranking is), and make sure they stay up once they get there.
I mean, if I go out and play my local 5-man event this weekend, should that effect my liklihood of being pushed to Novice at Cup? Of course not - it's two totally different animals.
- Chris