It turns out the switch is easily adjusted. Here's a pic of the innards of the switch when the clutch pedal is not depressed:
There's a set of stationary contacts (only partly visible under the spring) in the housing that the electrical connector attaches to, and a set of contacts attached to a spring-loaded slider block inside the housing. When the clutch is depressed, it pulls the rod to the left of the picture. At a given moment, the adjuster clip attached to the other end of the rod contacts a snout on the slider block sticking out of the housing. As the pedal is further depressed, the adjuster pushes on the snout and slides the block inside the housing until the contacts on the underside of the block close the circuit between the two stationary contacts.
So, knowing how it works it's clear that if your pedal needs to be pushed all the way to the floor before the contacts close, then you need to unclip the slider limiter from the end of the rod, and reclip it on a little closer to the snout. If you look carefully, there is a pair of small hooks on the slider limiter holding the two halves together. You only need to unclip one side with your fingernail to move the limiter along the rod.
Also notice that there are a pair of teeth on the inside of the limiter that must engage with the teeth on the rod to make a positive lock onto the rod.
Lastly, it might take a few tries to get it just right. The last thing you want to do is install the limiter too close to the snout on the block and end up having the internals of the switch act as the pedal stop. It will surely break if you do that.
[This message has been edited by Bloozberry (edited 06-10-2012).]