I don't know the bidder, but wow, <A href="http://cgi6.ebay.com/ws/eBayISAPI.dll?ViewBidItems&userid=336699225588&completed=1&all=1&rows=25&sort=3" target=blank>he/she has been bidding up a storm!</A>
I don't like private fb either, but so far it's all positive (100% fb), including multiples from the same sellers, so that's a good sign.
You could always put something in your auctions about private feedback bidders not being allowed, or having to e-mail you first.
Laura