I think you are going about this the wrong way, as doing something like that could take up to a year of map making and heavy scripting, bug testing, and so forth.
NikT is right about the grid positions, a script that could do that would be great, that way its more like a prober tournament, but would also need a lot of time to get done, to make sure it is all working properly.
Best idea would be go around the community and find clans that would be willing to join this, then start from there, you would have a set number of clans, then set a number of members to represent them, after all, this is for a title of the best racing clan. once you have that, then start making maps around the criteria, watch the racers, see there strengths and weaknesses, then try and make a map around that, endurance racing would be one of the best type of maps, but try make it all terrain, it gets boring racing on the road all the time.
think about how long each map would need to go for, if you are going for endurance, a longish time would be good, say 10-15mins or longer, no longer then say 30, you want to keep the players interested after all. try to use a range of vehicles as well, maybe not constant vehicle swaps during a map, but on different maps now and then, or have random pick ups around the map for people to chose from, or as what SiK were use to, set up a voting on a main forums with a list of vehicles, the top voted vehicle is used.
Allow each clan to nominate a representative on the forum, one person gets to speak for the whole clan, that may leave a lot of stress on that person, but its better then a big spam fest and arguments happening every where.
I think you should make it something like a knock out tournament, each clan gives it all and after a series of racers, the ones with the lowest score gets knocked out and has to wait till the next tournament starts again, but make sure its got a few levels to go through, but you would need to do what i said earlier about seeing how many clans actually wish to participate in this
for example, im going to say 5 clans have said yes to this tournament
im going to say SiK, SKC, NIR, AGS and DRuG
the first series of races could be out of 5 maps,
and you would need to get a minimum of 3 points to get to the next stage
slowly raise the minimum level until you have your final two clans, but leave the last map a secret. that way nobody but the creator/admins will know what the map is like
thats just my thoughts on how to do it, hope it helps you out