Dunlop Crybaby Mods
For electronic mods, check out
http://www.wah-wah.co.uk/index.html
http://www.diyguitarist.com/DIYStompboxes/WahMod.htm
I haven't gotten my Crybaby sounding the way I want it yet so I can't suggest a particular set of mods, but here's a good one that's barely documented on the internet, is very easy to do and undo, and requires little time and no soldering. In a nutshell, you move the position of the wah pot so that the sweep range is shifted towards the bass side. This helps to get rid of the icepick treble in the toe down position.
The stock Crybaby uses a rack and pinion gear setup to sweep a pot based on the pedal position. However, the full sweep of the pot is not used, which means we can shift the sweep one way or the other.
First, unscrew the four screws on the bottom and remove the bottom plate. You will see something like this:
The white plastic bit on the left holds the rack and pinion together:
As you can see, the lubricant tends to fill up the pedal with hair, pet fur, or whatever's floating around. Anyway, put the pedal in the heel down position and unscrew and remove the white plastic part. Note how at the tip of the pot shaft there is a metal cap with a flat side. Write down the position of the flat side so that you can return the wah sweep to the stock setting if necessary.Then, carefully pull the black rack away from the pot.
Now, rotate the pot 1 or 2 notches clockwise, push the rack back on, and replace the white piece. Test out the wah, and tweak the setting until you're happy. Then, put it all back together and enjoy your newly un-icepickey wah.