Forget the league and structure, all that is really needed is a governing body for current leagues and tournaments to operate under, to control or register individual players.
I agree about forgetting the league structure, at least for now. US Lacrosse is the logical choice to institute player registration. Local Chapters are already in place and most Club Teams require a US Lacrosse membership for insurance purposes anyway. The new Youth Rules do require a Birth Certificate for each player to be on file for US Lacrosse sponsored events. It does not seem that difficult to have US Lacrosse sponsored tournament registrations go through the membership database to be verified.
The question becomes will Club Teams support US Lacrosse sponsored Tournaments? Will the existing circuit of tournaments volunteer to abide by US Lacrosse rules or will competitors that are US Lacrosse sponsored have to lure Club Teams away?
This all seems very possible up to 8th grade.
Is there any HS player that plays on a Club Team who is not interested in playing (at whatever level) in college? Everyone I have ever encountered always thinks that lacrosse will benefit the players search for college. Some do not always play, but the goal is that lacrosse will "juice up" the college application in some capacity.
Has lacrosse reached the point of having the numbers to support both competitive and recreational Club Teams through HS age? It is very possible that I am ignorant, but I don't see it.