We've considered lots of different top 10 lists, but tend to shy away from performance-based lists. We do this because the site is so easy to game and lets users post fake data if they wanted.
Right now, there's no real reason to do that (we don't list the highest MPG first in any listings) but if there was an incentive like you get to appear first on every page for your car, you can bet some people would be inclined to goose their rankings a bit.
And considering we have lots of car clubs on this site that are very proud of their chosen vehicle, I could see a pretty easy concerted effort from a small group attempting to push their car into the top slot for bragging rights.
Leaderboards are something we avoid here for all these reasons.