Does anyone know anyone who's ever successfully sued a non paying Ebay bidder? 
Local laws apply and they vary. On German ebay I see it a lot that sellers refer to legal action in case bidders do not follow through. Must be a common thing there.
Because some people have a wrong understanding of ebay (like our man)
According to German law, an ended ebay auction is no an auction but a sales contract.
And contracts have to be fulfilled.
In this case here, the seller is a private person and he did not offer to take the item back. So he doesnt have to.
Further more, I cant see any evidence of fraudulent misrepresentation.
So on what basis does he cancel the contract? Because "ebay" said he can do so ??
