Alright, let's do this

http://www.tf2outpost.com/trade/11493842

- TONS of adds for 12

http://www.tf2outpost.com/trade/11980355

- offer of 12 robokeys

-offer of 10 keys+s.eternal ~ 11.8-12

http://www.tf2outpost.com/trade/11057392

- offer of 13 robokeys

- offer of 10 keys+s.shotty+s.amby ~ 12.8-13

- sold many for 12

http://www.tf2outpost.com/trade/10598365

- steaming billy ~ 13 keys and other unusual offers

http://www.tf2outpost.com/trade/6196750

- rejected many 11 key offers

http://www.tf2outpost.com/trade/11875434

- 14 in items

- ts bills+3 keys+sweets = 11.5 + sweets

http://www.tf2outpost.com/trade/12041167- sold for 12

http://www.tf2outpost.com/trade/12071835- sold for 11 with 4 views

http://www.tf2outpost.com/trade/12026950 - sold 2 @12

http://www.tf2outpost.com/trade/11812937 (offers of 12 keys, Big Kill(13 keys easy), 8 keys + Crate #40(12 keys min))

http://www.tf2outpost.com/trade/11657652- SO MANY OFFERS FOR 11 KEYS...has a retracted offer of 12

- offer of smoking toe~ 12 keys

http://www.tf2outpost.com/trade/11499182 - retard

http://www.tf2outpost.com/trade/7812027- offer of 11.4

http://bazaar.tf/trade/264460

- a gifted but tradable juju+a key (not sure what the value is, but i'm pretty sure it's higher than 12)

http://www.tf2outpost.com/trade/7071592

- offer of nuts geezer ~ 12

http://www.tf2outpost.com/trade/11558372

-nuts inspector ~ 12

- lots of rejected 11 key offers

http://www.tf2outpost.com/trade/11090837

- $21 offer ~ 11.5

http://www.tf2outpost.com/trade/7007157

- flies mongolian

- nutes stuntsman

"BTW, feel free to use my suggestion and create a 11 - 12 key suggestion if you feel strong enough" - KeyofHearts. Some credit of proof goes to KeyofHearts.

Sort of hard to sell for 12 keys, but very possible, and many offers of 11 keys are getting rejected. Also lots of unusual offers.