You can try remapping control to caps lock.

Other than that, the Kinesis is your best bet (I use one myself and use the backspace thumb button as a modifier key).

Tomlu: I tried remapping Caps Lock to Control (it's a popular thing amongst old school UNIX users), but it is actually not a solution: it still overworks the (left) pinky, and it forces your hands into even more awkward positions for certain combinations.  One thing I should definitely start doing though is using opposite hands for key combo's, but even then I tend to press Shift and Control too hard so it becomes painful.

DreymaR: how would you "easily" attach random pedals to an USB connection?  Or are you talking about serial connections (easy) and writing a custom serial keyboard driver in software? (may be relatively easy as well)  Unfortunately most contemporary pc's come without serial ports so USB is the only way to attach devices.

About switching Ctrl and Alt to be able to use the thumbs for Control: the thumbs may indeed be stronger, but even they don't like the awkward inward move you have to make to press the keys next to the space bar...  My thumbs tend to get sore from many consecutive Alt/AltGr combinations as well...  (again I think because I'm pressing too hard)  Using the palm of the hand for Ctrl works on some keyboards, but it is far less precise then using the fingers.

Another software solution I'm currently trying is "sticky keys".  It means entering key combo's in "serial" instead of in "parallel", eg. Control+A becomes "Control, then A", so you don't have to "chord" the keys anymore.  It seems like a good solution and is available by default on Windows, Mac and X11.  But on Windows it doesn't work together with PKL. :-(

Thanks, that looks interesting!

Chording correctly is recommended but probably won't help much for your pinky pain.

I tried pedals but didn't like them. They force you to sit in a single position which can become uncomfortable. Other people swear by them though so it's something you'd have to try.

Very good point.  Thinking of it, I tend to sit in different positions with my legs (under my chair, in front of me, ...), so being forced to sit in a single position may indeed be uncomfortable and annoy me pretty quickly.

I'm currently testing sticky keys (so chords become sequences) and it seems like the best way to go.

Ironically, while this was invented by Microsoft, it doesn't seem to work very reliably on Windows (Vista), but it works flawlessly on X11 (with the AccessX extension).  On Windows this may be due to the combination with other key-manipulation software (for Colemak) though; with PKL it doesn't work at all, and with my AHK-compiled binary it sometimes seems to "get stuck" on a modifier key which is then (virtually) pressed all the time.  Very annoying and confusing.  On X.org, keyboard layouts live in the same layer (xkb) as the sticky keys and other tricks, so it doesn't interfere (and Colemak is now a "native" layout just like all the others).