This hat hasn't been updated in a while, so I decided to do so. These are all the trades and histories of the hats that I could find on outpost. Please leave comments with suggestions or better ranges.

Listings on backpack.tf: 26 keys (this isn't really proof, but I'm trying to add everything possible)

http://www.tf2outpost.com/trade/18079870

B/O: n/a

C/O: 1 bud + 10 keys (1.5 buds, but he doesn't have any proof of this, says the buyer is on his friends list)

Offers:

Stormy Storm Honcho's Headgear (about 1.7 buds after overpay) + sweets from the seller, so I'd guess that that would put this offer at around 1.3-1.5 buds

Stormy Storm Nanobalaclava (about 1 bud after overpay)

Professional Killstreak Ham Shank (no idea how much this is worth)

History:

http://www.tf2outpost.com/trade/17687662

Offered an Australium SMG + sweets (about 18-20 keys)

Pretty much all I could find, no sales

http://www.tf2outpost.com/trade/17842332:

B/O: 26 keys I guess?

C/O: n/a

Offers:

18 keys

Craft #3 for a hat (not sure about value)

History:

nothing definitive, and still no sales

http://www.tf2outpost.com/trade/16529884

B/O: n/a

C/O: over a bud

Offers:

20 keys

1 bud + 1 key

Steaming Hermes (1 bud after overpay) + 2 keys, Total: 1.1 buds

18 keys

Full Festive 2011 Wep Set (about 18-20 keys)

Professional Killstreak Bushwacka (not sure on this value)

Bubbling Buccaneer's Bicorne (1.2 keys after overpay)

18 keys, then 1 bud

the same killstreak ham as before

History:

http://www.tf2outpost.com/trade/16064134

Sold: for 1 bud

That was about as much as I could find for this hat. Please leave you opinions in the comments, its nice to know what people think about my suggestion.