What would you think of this: incorporate teams (not necessarely based on country*). every team has a team captain (and name, logo, ..). Every pilot can choose to participate in a team, but the captian must approve the "membership". everyone can start their own team.
To score the teams, I would use the same principle as the AAS scoring. Each day, sum of all team members' score divided by number of team results +1. This will ensure you need around 4 pilots per team each day to be able to get a good score. The more pilots your team has, the closer you will get to the actual average dayscore of your pilots (but the more you have, the more likely you will be to have some sub average pilots or results too).
Per month, same idea; sum of dayscores per team divided by number of days flown +1. *edit* had some comment here about counting only pilots that flew 2+ races, but that makes no sense with this scoring, since we take ~averages of each day, so it doesn't matter for team result if a certain pilot only flew once */edit*
Overall teamscore, I'd use the same principle as overall LLC ranking, but I'm not sure yet how we will do that. "Averaged+1", place scores (5 out of 6 or not?).
This would be quite flexible for pilots that don't fly each race/month, they won't ruin the team's score. It would also allow people to join a team later without messing up the scoring. Lastly, this approach also requires balanced teams; too few pilots won't get good scores (due to +1 AAS thing), too large teams will score just average.
For LLC 2008
(or who know's, maybe 2007 if it rains all summer) we might even set up a private forum for each team to discuss tactics and stuff.(*) I'd probably still keep a "country cup", but with very simple scoring: average of all pilots for that country.
