Nomes...
I'm going to have to agree with dadio here. I think you'd be opening yourself up to a huge can of worms. I can do basic cover design, so can just about everyone with a couple tutorials in GIMP.
What you propose sounds almost like a vanity press, which will most likely get you all sorts of freaks and weirdoes. Plus, it would be your (professional) reputation at stake. You'd need to be a gate keeper to filter out 98% of the junk. I've read slush piles before. I know the kind of crap they get. And I'm sure you know too.
The only thing I'd be worried about is the ePubs come and go...i don't want you to overwork yourself for minimum pay..I think you'd probably have better luck workin as a freelance editor. I've looked into the concept and several other guys here have too. I think it usually boils down to start up costs and stuff.
But hell, I wish you the best of luck. Hopefully you won't need it. If you need a hand tho, let me know.