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If you mean by fast moving a low pin-to-pin delay (like 2 ... 5ns) then you will end up to a macrocell (super PAL) based architecture. These devices have a very predictable delay in the order of magnitude of 2 ... 10ns (the fastest device is an LC4032C-25xxc, but not Xilinx) fastest device of Xilinx will be a Coolrunner alike.