Outdated, so going to give a slight adjustment.

http://www.tf2outpost.com/trade/13895331

Selling for Bud + 2

Notable offers: White Blizz Glove (19)

http://www.tf2outpost.com/trade/13466972

Selling for 18 keys

http://www.tf2outpost.com/trade/13465527

Selling for a bud or 22 keys

http://www.tf2outpost.com/trade/13347792

Selling for 23 Keys

http://www.tf2outpost.com/trade/4400528

Up for almost a year, recent offers are just unusuals in the 20-22 key range

Traded a stormy mirror for one a long time ago. (21)

I forget what I sold it for and I can't seem to dig it up, but speaking from experience, this thing is a pain in the ass to sell. Which consequently seems to be the reason why I can't find solid sells for proof. There a great deal of b/o's in the lower range though, and absolutely no offers close to 28 keys. Feel free to provide counter proof.