Not without creating counters and registers and binary adders...and you've just created a macro-computer. The 8-pin µC is going to be your smallest, and probably cheapest solution.
Use an resistor-capacitor circuit with a diode to bypass the resistor when the capacitor is discharghing. Then add a transistor to bypass the resistor when you do not want to shorten the pulse width.
That should be all you need. Play with The RC values until you get the offset that you need.
Thanks This forum is awesome. But that still leave an issues of how much the pulse is shortened needs to be ale to be different depending on the current pulse rate going into it.