Word of advice . . . probably would have nothing to do with you.
Don't flood CraigsList with a bunch of used bikes (no matter how good the condition), day after day, and list them as if they are individuals selling them and not a company.
We have a bike shop in Chicago, which sells (as far as I can tell) only used (and mostly crappy) bikes, probably post upwards of 10 ads a day on the Chicago CL. If anyone is in Chicago and has visited the Chicago CL lately they will know what "store" I'm talking about.
Constantly get flagged, repost, etc. People have even RE:Flamed them over and over. It really makes them look crappy and a**holish.
As a layperson, I wouldn't recommend selling used bikes along with new bikes. You will either be a "used" store with some new bikes, or a "new" store with some cruddy bikes. You are talking about catering to two potentially different clientele, I'm sure it could work, but most likely not well. Think about it, someone comes in looking to drop a thousand+ bucks on a roadie, and they see some old vintage bikes for sale, and think, "wow this is kinda low-end", and go elsewhere. Conversely, a college kid might come in looking for a cheap and reliable vintage bike, and see a bunch of new roadies, and think, "wow this is out of my price range", and go elsewhere.
Even if you had really nice vintage bikes, unless you are catering to C&V type riders, the general bike riding public will just see them as old, cruddy bikes.
My recommendation, flip your 43 bikes personally though CL, and invest that money in the store. Keep the vintage/new completely separate.