Rarity:

6 in the wild

3 on outpost

http://backpack.tf/unusuals/393/Villain%27s_Veil

TF2PC consensus: 18-20

http://www.tf2pricecheck.net/Thread-PC-Massed-Flies-Villain-s-Veil

Trades & offers: (2 dupes)

http://www.tf2outpost.com/trade/7536426

-$510 or 16 pure (From a veil collector)

-Sunbeams Bonk Boy, 1 bud and a crate 40 (~17.8)

http://www.tf2outpost.com/trade/7970671 (Clean)

-secret ywn (~17)

http://www.tf2outpost.com/trade/5423316

-Flies TC + Stormy 13th hour brigade helm (~18)

-Harvest Moon Hustler's Hallmark (~14)

-Claims to have been offered 18 3 times and 19 (take that however you want)

As usual, if you know other information, please chime in!