Don't you think that'd become the "B-team" pretty quickly, though? I think it might fall apart. What might also work is something more like the "pro bono" model of lawyers? Make it a marketing thing, maybe see if the big clients would want to get in on the PR benefits of helping the little clients, maybe rotate your rockstars through the smaller projects and help develop less-experienced talent that way?
It has the risk of being a B-team but it's also a good way to onboard new hires. You get a much higher turnover rate of new things to try, do, and learn. One place I worked did communications generation (PDF letters etc), we had massive clients and 300 hour projects and we had 3 hour simple letters. Churning those small ones out was the best way to get me to learn when I signed up. Just as long as someone sensible and experienced is watching. And some people just don't gel well with project marathons - I'm definitely a sprinter who loses focus on huge projects despite my years of experience. I'd rather do a lot of small ones.
It eventually got sold to a bigger more respectable company and those 300 hour quotes crept up north of 1000 hours and it was impossible to finish any job in under 10 hours but that's another story about internal red tape.
Other way around, in my experience. We run a team of ~20 at our studio—the "A-team" all want to work on the smaller projects because they're usually more interesting, they have more control, they get to move faster, etc.
