Sounds like you're toast if a site requires a VIN, unless you contact them and they can override the problem.
I've had great luck with
www.craigslist.org and you don't have to worry about the VIN. The local newspaper should work, too. I'd disclose the car's grey market up front in the craigslist ad and over the phone on a newspaper ad. That is relevant to the value.
You don't need to put the VIN in here on Pelican, do you?