This page provides a variety of modifications to enhance and extend the Vex robotics system.  Of course, modifying a product voids its warranty, but I think such modifications are in the spirit of the VEX system.  Certainly the metal parts are intended to be modified, so why not the electronics too?

How to Mod…

SPDT Vex Limit Switch

This reversible mod shows how to convert an SPST Vex Limit Switch into an SPDT Limit Switch.

After the mod, you can still use the limit switch with a Vex controller as before, but you can also use it with the VRC Limiter project.