This is what you want. Don't know if they're available in the USA.

http://www.carfi.co.uk/html/autoclutch.html

http://www.vehvac.co.uk/brochures/autoclutch-leaflet.pdf

If I'm not mistaken, the late 60's VW Beetle manual/auto used some kind of system like this.

__________________
1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13