(I usually have PayPal make payment AFTER inspecting the purchase, but he avoided that).
That's a very limited programme, which most sellers dislike and do not use. As I understand it, the buyer has to pass inspection by Paypal since PP actually pays the seller, and accepts the risk.
But all in all, this does sound like a scam. Don't pay. Ignore him. A 24 hour auction for a high price/high fraud item, offered to the second chance buyer , and off-eBay billing? Nuh- uh.
The worst that can happen is that you get an Unpaid Item Dispute. Unlikely since these crooks don't like to draw attention to themselves. If you do lose a UID, your general good buying practices will make it unimportant. (But if you get a second Strike, you will find it very difficult to buy on eBay at all).