The only one I can recommend in your price range that meets the maximum of all of the aforementioned specs is one of the Korean monitors.
The QNIX QX2710 is a 27", 1440p monitor that can be overclocked up to 120hz. I see a lot of people online who typically get a max of 96-110hz, but your mileage may vary. It's usually around the $300 range, but make sure to get the single input version. Any of the other versions (multi input with displayport, etc.) may be harder to overclock, or may not overclock at all. The risk of these ones is definitely the warranty, as it is being shipped from South Korea, customer service in any manner may be a pain in the ass.
Otherwise, the Tempest X270OC monitors meet the specs. They have a glossy version for $450, and a matte version for a bit out of your budget at $500. These are kind of tough to come by, but you'll definitely have an easier time with the warranty and customer service as the company is based out of the US.
