Thanks for the ideas.
What I'll try is the 2 bit counter where the clock input is the switch. I'll also use the switch to trigger a timer that will reset the counter after a short delay. If I get a quick double press, the 2nd bit of the counter will go high before the reset. If not, the timer resets my counter.
The 2nd bit output of my counter triggers the circuit to power the window motor (I already have a window circuit to monitor the motor to determine when it stops).
For normal window operation I'll have another circuit that also monitors the switch, and if it detects a press longer than, say, 200ms that it will activate the window motor as well.