Some proof was missed from the last suggestion (I don't blame them, though):

http://backpack.tf/suggestion/5860d06e0e2cad567623cdd1 (Suggested at 29 keys)

Sale #1:

http://www.tf2outpost.com/trade/28628935

Max (18) + Duped 1st gen Peace Baker's (22) = 40 keys; caps at buyout of 36 keys

http://www.tf2outpost.com/trade/28601524

http://backpack.tf/profiles/76561198194767263#!/compare/1478908800/1479254400

http://backpack.tf/profiles/76561198080179568#!/compare/1478822400/1478908800

Sale #2:

34 keys

http://www.tf2outpost.com/trade/28628935

http://i.imgur.com/fgXUYke.png

http://backpack.tf/profiles/76561198080179568#!/compare/1480723200/1480809600

Sale #3: (duped sale)

GFetti Thirst Blood (20) + SGG Deep Fried Desire (16) = 36; caps at buyout of 34 keys

http://www.tf2outpost.com/trade/28660447

http://i.imgur.com/foJuyuW.png

http://backpack.tf/profiles/76561198164648942#!/compare/1481846400/1481932800

http://backpack.tf/profiles/76561198080179568#!/compare/1481846400/1481932800

Minis:

Gfetti Thirst Blood + Deep Fried Desire:

Gfetti Thirst Blood sold for a Mem Leak Engineer's Cap (16) + V. Luger (4)

Mem Leak Engie Cap sold for 16 keys

http://i.imgur.com/foJuyuW.png

http://i.imgur.com/UDrxjAU.png

http://i.imgur.com/Tv55yvv.png

Using the 29 key sales from the previous suggestion and the 34-36 key sales in this suggestion, the complete range should be 29-36 keys.