As shown in the last suggestion, it had already gotten an offer up to 1.75 keys. Multiple buyers at 1.4 keys

Offer

http://www.tf2outpost.com/trade/9365834 (5 keys for 3) ~1.66 keys each rejected

Buyers

http://www.tf2outpost.com/trade/10982059 (1 bud for 8 haunted blazing bull + buzz killer set) around 1.27x current price, but may be slightly invalid due to paying for convenience ~1.9 keys each

http://www.tf2outpost.com/trade/10079705 (1.4 keys unsuccessful) last one 3 week ago

http://www.tf2outpost.com/trade/10651139 (1.4 keys successful)