Take two Moog Ethervox Theramin devices. Place them a foot or so apart.
Take their respective MIDI outputs and plug them into your PC's MIDI port (you need to buy this as well).
Write a mouse-driver which converts the MIDI signal into the suitable 2-d coordinates; probably possible by triangulating
the two signals.
Voila ! A mouseless mouse, and great sound effects as you navigate through that boring spreadsheet and all for a mere $9,900. (maybe more, they're no longer manufactured apparently).
Oh - forgot about the mouse buttons - ok , some converted sustain pedals, and a Wa-Wa for the little wheel in the middle.
Seriously, I'm sure this would work with cheaper Theremins-type devices just as well.