16V8 PLD alternatives for fast clock-to-data turnaround time
I am not convinced that you really need programmable logic. The PSoC can update its data output ahead of time at the rising edge of the SCL, and use something fast to present that output on time to SDA when SCL falls. A tristate output D F-F, like 74LVC1G374 will do just that, with a propagation delay of 6ns max with 50pF load at 3.3V across temperature. Since the F-F needs to update on a falling clock edge, its clock input needs to be SCL inverted with e.g. 74LVC1G04, adding 3.3ns delay. You got 2ns to spare :)
If you want to drive larger capacitive loads, parallel a couple of those F-Fs. The inputs have 3pF typical input capacitance, so the maximum number of them in parallel depends on the allowed SCK unit load you can present.
You could probably make something a bit faster with discrete gold-doped switching transistors designed to stay fast even if driven into &quot;saturation&quot;, but nobody makes those anymore, I don't think - and it'd be a power hog.