This needs a drop.

Classified ads at time of posting:

http://m.imgur.com/qPukehp

http://backpack.tf/classifieds?item=Festive+Rocket+Launcher&quality=11&tradable=1&craftable=1

2*16 keys

2*16.37 keys (1 has kills under a full moon)

3*16.47 keys (1 has airborne enemy kills)

1*16.52 keys

Unsold at 16 keys and 9 refined (~16.5 keys):

http://www.tf2outpost.com/trade/26173381 (Has kills under a full moon, ~3 weeks)

http://www.tf2outpost.com/trade/26267977 (Has airborne enemy kills, ~1 week)

Unsold at 16 keys and 7 refined (~16.4 keys):

http://www.tf2outpost.com/trade/26267977 (~1 week)

Sellers at 16 keys:

http://www.tf2outpost.com/trade/26222383 (~2 weeks old)

http://www.tf2outpost.com/trade/26342336 (Has parts, pumpkin bombs and Exorcism, young)

This is all I could find on Outpost that are valid at the time of posting.