You might try the TurboSquid forum (www.turbosquid.com). A lot of artists there have characters for sale which aren’t rigged, and you might get some people interested in getting rigged versions to sell. Be sure to include the software you use.
To gain trust, you might download some of the free models at TurboSquid, rig them, and offer them back to the original artist via TurboSquid support. Artists are notoriously skittish about giving anything away, since so much stuff ends up on torrent sites. They might be worried they’ll send you a model and they’ll never hear from you again.