@loaffette just saw this question, sorry for the delayed response! I'm the author of that rewheel
project.
Currently, you can decrease the pushback + increase the Pint aggressiveness to give you higher speeds using those firmware patching tools. Past that, you could modify the Pint to higher current limits, but I haven't looked into doing that yet. As everyone else has mentioned, you run the risk of drawing too much current from the battery depending on the riding conditions (incline, rider weight, etc.).
The reason why the Pint X and the XR can draw more current (and have an even higher max speed) is because they have that second string of batteries run in parallel. Your safest bet would be to get an XR / Pint X until we find a way to dump firmware without pulling the chip off of board.