Not quite the bulk you're looking for but good prices:

2x RX580 8gb ASUS - $95
3x RX580 8gb Red Devil - $95
12x RX470 8gb Sapphire mining edition - $80
6x RX580 4gb Sapphire Nitro (Samsung memory) - $70

https://bitcointalk.org/index.php?topic=5157666.0