A push-to-start button should work, if you can figure a way to mount it to the shift lever. Any good FLAPS should have a listing for a generic starter switch, or one of the aftermarket suppliers like Cole-Hersee will definitely list one. Try a boat shop or a marina if necessary for a push-button horn switch- - - -same thing.
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!