I can see why no one wanted to do this.

February 23rd:

Sold for 1100 keys

http://www.tf2outpost.com/trade/27878859

March 1st:

Sold for 1100 key

http://www.tf2outpost.com/trade/27908793#

March 11th:

RA Viewfinder + Burning Chullo

http://www.tf2outpost.com/trade/27942842

http://backpack.tf/profiles/76561198060850032#!/compare/1457596800/1457683200

View is outdated, possibly underpriced. Should cap at buyout of 1200 keys

March 14th:

Cash

http://www.tf2outpost.com/trade/27956156

March 15th:

Sold for a complete set of level 1 Australiums?

http://backpack.tf/profiles/76561198264117779#!/compare/1458025200/1458284400

Would obviously be low if that's the case.

March 20th:

Cash + keys?

http://www.tf2outpost.com/trade/27960791

http://backpack.tf/profiles/76561198004478413#!/compare/1458457200/1458543600

March 21st:

Lots of hats, should exceed buyout of 1100 keys

http://www.tf2outpost.com/trade/27908776

http://backpack.tf/profiles/76561197980709148#!/compare/1458543600/1458630000

March 30th:

Bulk deal for Burning Pullover

http://backpack.tf/profiles/76561198064665641#!/compare/1459209600/1459382400

April 4th:

Probably cash

http://www.tf2outpost.com/trade/27956156

April 5th:

Sold for 1080 keys

http://www.tf2outpost.com/trade/27977276

http://backpack.tf/profiles/76561198036411686#!/compare/1459814400/1459900800

http://backpack.tf/profiles/76561198048864903#!/compare/1459036800/1459900800

April 6th:

Quick-sold for 1000 keys

http://www.tf2outpost.com/trade/28052373

April 9th:

Green Energy Stash (213) + 960 keys

http://www.tf2outpost.com/trade/28059076

960 + 213 = 1173; buyout was 1200 keys

http://www.tf2outpost.com/trade/28059076

http://backpack.tf/profiles/76561198048864903#!/compare/1460160000/1460332800

April 12th:

Sold for:

~150? keys

Purple Energy Crone's (1030)

Purple Fetti Beak (50)

150 + 1030 + 50 = 1230

May have involved other items, not sure.

http://www.tf2outpost.com/trade/28057397

http://backpack.tf/profiles/76561198092472594#!/compare/1460419200/1460505600

http://backpack.tf/profiles/76561198107383449#!/compare/1460419200/1460505600

April 16th:

Sold for 1100 keys

http://www.tf2outpost.com/trade/27928715

April 17th:

Sold for Duped Scorching TC

http://backpack.tf/profiles/76561197989600008#!/compare/1459296000/1461024000

April 19th:

Sold for:

Sunbeams Executioner (4 months outdated at 1150)

Bubbling Tyrant's (~20)

Purple Energy Ballcap (~150)

Kill-a-Watt Mask of the Shaman (~105)

Purple Energy Backwards Ballcap (~155)

Sunbeams Hermes (~100)

Death at Dusk Grimm Hatte (87)

Bubbling Merry (~14)

~120? keys in other items (80)

40 keys

1150 + 20 + 150 + 105 + 155 + 100 + 87 + 14 + 80 + 40 = 1901; rounds to 1900 keys

Most of these are outdated, but that should be pretty generous overpay.

http://www.tf2outpost.com/trade/27979570 Buyout was 1200 keys, also declined 1000 keys

http://backpack.tf/profiles/76561198057254231#!/compare/1461024000/1461196800

http://backpack.tf/profiles/76561198003161689#!/compare/1460851200/1461196800

April 26:

FoD Pool Party (1100) + Abduction Space Mann (200)

1100 + 200 = 1300 keys

http://www.tf2outpost.com/trade/28113297

http://backpack.tf/profiles/76561198001106243#!/compare/1461628800/1461715200

April 27th:

Sold with Dusk Viewfinder for Knifestorm Coffin

http://backpack.tf/profiles/76561198032034038#!/compare/1461715200/1461801600

April 28th:

Quick-sold for around 1000 keys

http://backpack.tf/profiles/76561198183804189#!/compare/1461801600/1461888000

April 30th:

Level 1 Pan

Sold for items which should well exceed 1200 key buyout

http://www.tf2outpost.com/trade/28122115

http://backpack.tf/profiles/76561198085269574#!/compare/1461888000/1461974400

http://backpack.tf/profiles/76561198092673085#!/compare/1461888000/1461974400

April 30th:

Strange Burning Wrapped Hat + Strange Burning Chullo

http://www.tf2outpost.com/trade/28117762

May 3rd:

Sold for:

850 keys

Duped Scorching Phantom (~120)

Stormy 13th Dead Cone (~40)

Peace Conquistador (~28)

Professional Killstreak Australium Knife (~32)

Strange Factory New Shot to Hell Scattergun (~16)

850 + 120 + 40 + 28 + 32 + 16 = 1086; rounds to about 1100 keys

The pan was not listed on Outpost. Pretty close to 1100, and mostly in pure.

http://backpack.tf/profiles/76561198033941181#!/compare/1462233600/1462320000

http://backpack.tf/profiles/76561198050052801#!/compare/1462233600/1462320000

May 3rd:

Sold with ~100-ish keys in other stuff for Spellbound Antlers

http://backpack.tf/profiles/76561198104991389#!/compare/1462147200/1462233600

... of which the Spellbound Antlers has an open suggestion to be updated from this sale.

http://backpack.tf/suggestion/572a4d9d83de6b188319f9ec

Sales are:

1000 (April 6th, keys, quicksell)

1000 (April 28th, keys, quicksell)

1080 (April 8th, keys)

1100 (February 23rd, keys)

1100 (March 1st, keys)

1100 (March 21st, buyout capped)

1100 (April 9th, mostly keys)

1100 (April 16th, keys)

1100 (May 3rd, mostly keys)

1200 (March 11th, buyout capped)

1200 (April 19th, buyout capped, 1900 in mostly Unusuals)

1230 (April 12th, mixed, mostly Unusuals)

1300 (April 26, Unusuals)

Sellers:

http://www.tf2outpost.com/trade/28080574 1149

http://www.tf2outpost.com/trade/27992539 1200

http://www.tf2outpost.com/trade/28115539 offers

http://www.tf2outpost.com/trade/27570580 offers

http://www.tf2outpost.com/trade/28147963 cash

http://www.tf2outpost.com/trade/28080574 cash

http://www.tf2outpost.com/trade/28117830 cash

http://www.tf2outpost.com/trade/27499963 as a set

Fewer sellers than usual, currently!

Classifieds Currently:

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

Conclusion:

I know I'm probably missing many sales, but this should be a good amount of proof. Many of the sales at 1000 keys are true quicksells. Many pure sales at 1100 keys. 1200 keys is still a common selling point, and many sales cap at that value.

Value here should be around 1100-1200 keys.

Additional proof/counter-proof is very welcomed.