Re-doing once again, thanks to polar bear for the feedback on my last suggestion!

Only 3 exist.

Sales:

http://www.tf2outpost.com/trade/17756275

sold for 4 buds pure

http://www.tf2outpost.com/backpack/76561198065741250

This guy has 4 buds in his backpack-the previous owner of all 4 buds, ɥʇlɐǝʇS, currently is selling the hat here -> http://www.tf2outpost.com/trade/17890991

http://www.tf2outpost.com/trade/17794327

been offered 5 (collecting), and considered 4 (4.5)

Offers (from polar bear):

~5 - searing honcho + eerie stovepipe ~5

~5 - aces sam + stormy bonk (aces sam sold for ~2 here http://www.tf2outpost.com/trade/17365606 )

~4.2 - phos hw + ~0.8 in stuff