First off, this is not an actual antique. It is a recreation of a 1905 Harley-Davidson 3 ½ HP built in the mid-Nineties.
Nonetheless, it's pretty impressive. Only five of these repros were built, and number 5 popped up on eBay last week. It's built from original drawings and is supposed to be as exact a copy as you can possibly make. And it's never been started!
Call it a reproduction, call it art... whatever. It's pretty cool.