When I was a younger man, before I became the old and decrepit 24 year old before you, there was a little-known game not much unlike this one. It was fun, nerdy, made by a small yet very active company (before Microsoft got it, I guess), and had a small, dedicated community of players. Okay, not "Holy crap there are 200 people on ICO at the same time?!" small, but you get the idea. The game was Mechcommander and one of the leagues formed around it went by the name of Steel Command.
The SCL was a heavily role-played league which used Mechcommander as a vehicle to wage an enormous interstellar war between the various Battletech factions (faction websites still exist today, in all their 1998 glory). Factions would fight for territory and resources. They would commit Mechs and other resources to battles, then play out those battles in the game. There was diplomacy and even an enormous map which was manually updated to reflect faction ownership changes (this was back before the web was "dynamic" 
I think a league like this would work well in Sins for a few reasons. First of all, it is asynchronous. That is, factions can schedule games or just issue orders ("Explore this planet", etc.) and won't need to randomly have a whole lot of players on at the same time (this is the main reason clans don't work right now). Secondly, Sins is very customizable, which is required for this sort of thing to work. The Map Designer is quick and dirty, but the real power lies in Galaxy Forge (assuming it gets fixed) which allows maps to be custom-tailored to battles. With this customization combined with the fact that different battles can have different supply caps, sizes and so forth, games can be long or short depending on the battle setup and include any number of other variables.
Sins games can be incredibly long, back and forth, intense experiences even though the action isn't necessarily constant -- that's what I love about it. You have to make big decisions -- do I build up and dig in or rush? Do I save that planet being attacked or do I counter? -- which can affect where you are an hour later. But what if the game didn't end in an hour, a day, or a month? What if there were an entire Universe to conquer and not just a star or two at a time?
If there's a game out now that could be used to resurrect the enormous scope and breadth of Steel Command, it is almost certainly Sins. However, this is no minor task and will require dedication and effort from many -- not to mention players! I'm not sure if we have enough people yet, but we'd have to start somewhere. This would be a considerable undertaking and I am already extremely low on free time, so I'm putting this out now to see what sort of interest there is, if any. Please provide feedback!
P.S. If you're wondering who would actually make the site for this, the answer is me. I do it for a living so we've at least got that part covered.
IMPORTANT ANNOUNCEMENT!
Like what you've read so far? Then check this out!
Okay folks, it seems like we have enough people interested to make an official inquiry here on the boards. The way I see it, we need a minimum of 25 people to start really getting the ball rolling in an official way on this thing. To that end, I have created a form that interested parties should fill out. It shouldn't take more than 30 seconds and will give me a way to keep track of people with serious interest.
One of the questions asks what you want your "role" to be; I have created the following roles with my recommendation of minimum numbers to fulfill in parenthesis (assumes 3 initial factions; one for each race):
- Steering Committee (3) - These are folks with experience with Sins and the sort of league we're trying to build. Their job will be to steer the league in the proper direction and make final decisions on implementation details. Of course everyone in the league gets a say in what happens; the committee is around merely to keep us on course, break stalemates, etc.
- Faction Leader (3) - These people should enjoy Lore creation and leadership. Their job will be to build up their respective factions, recruit members, define in-faction rules, ranks, etc. They are the backbone of their faction and should be creative types who can figure out innovative ways to get new members and make their faction more appealing to players.
- Faction Member (15) - These are the folks who want to help their respective factions take over the Universe. We need at least 5 normal members per faction to allow for max-size games and not make the faction leader have to play all the time (they will be busy enough!)
- Map Maker (2) - These guys allow us to play the actual game by creating the appropriate maps. They should be able to use Galaxy Forge (does it even work? Instantly crashes for me...). They'll also be map designers in that they will have a lot of opportunity to input their own ideas into the maps.
- League/Forum Admin (2) - These folks keep the lights on and everything humming along on the forums and in the league. Their duties will be extremely diverse.
Fill out the form here: http://binjured.wufoo.com/forms/sins-league-signup/
Thank you in advance!
(Entrenchment required for membership for the time being; with more players, hopefully we can have two leagues... but that's a dream for now.)