This works pretty much the way it does in a Terminal window. Selecting this brings upa File Requester which you can use to choose the app that will be launched by the hotkey. Most of the GUI for SpicyKeys is based on Brian Tietz's ColumnListView classes, from his Santa's Gift Bag package. SpicyKeys is FreeWare. Do whatever you want with it, although if you redistribute it, please keep the archive intact.
Source code is included, go nuts.
SpicyKeys is written by Jeremy Friesner.