anyone seen AMP discontinuing its co-location server? which other futures broker offers a co-location server and brokeage?

Haven't heard that yet & we have an AMP account. One option is to fight fire with fire. In other word co-locate yourself and your orders. Run your platform(s) on a VPS. For example, if you trade on the CME, the data center across the street is a good option (1ms from 350 E. Cermak). For the east coast, servers are located close to Mahwah, Carteret & Secaucus. sam028 can help you out there (speedytradingservers.com) Hope this helps