Classifieds as of the post of this suggestion:

x1 at 4 Keys. ( http://i.imgur.com/L2sKBhe.png )

x1 at 4.49 Keys. ( http://i.imgur.com/RB851ug.png )

x1 at 4.62 Keys. ( http://i.imgur.com/yYQPdjU.png )

Sellers under 4.7 Keys:

http://www.tf2outpost.com/trade/17274856 - 4.4 Keys.

http://www.tf2outpost.com/trade/17282317 - 4.4 Keys.

http://www.tf2outpost.com/trade/19570972 - 4 Keys and 3 Refined (~4.4 Keys.).

http://www.tf2outpost.com/trade/19897493 - 4 Keys and 4 Refined (~4.5 Keys).

http://www.tf2outpost.com/trade/19965483 - 4 Keys and 4 Refined (~4.5 Keys).

http://www.tf2outpost.com/trade/19953019 - 4 Keys and 5 Refined (~4.6 Keys).

http://www.tf2outpost.com/trade/19916883 - 4.6 Keys.

Unsolds:

http://www.tf2outpost.com/trade/19773509 - 1 Week+ old. - 4.7 Keys.

http://www.tf2outpost.com/trade/19786801 - 1 Week+ old - "bp.tf price" - This person has 4 dupe trades up of this item.

The rest that are up on OutPost are either Killstreak or priced above 5 Keys.