Jeeze...figure I would've have thought of this before...
The PWM (which I'm using as a variable frequency generator) on the 18F4685 @ 40Mhz will go down to ~2441Hz, I need it to go all the way down to zero or as close as I can get it, and go up to about 533Hz.
I take that PWM output from the '4685 and use it as the clock for an external 12F683. Very simple firmware in the '683, increment a counter and toggle an output pin at a fractional rate.
So, basically I end up with an over-engineered, over-thought, overly complicated, 'divide-by-2441' counter.