If somebody wanted to rig up a vacuum assist for a clutch, just mount a motorcycle brake lever onto the shift handle, and use the cable to operate a spring-loaded ball valve to control the vacuum.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!