Hello David,
     I have been thinking about using a single screen display for gauges
too.  I have a 8085 CPU on a small mother board, that I think would make a
good base for such a system.    It contains 2K of ROM and 256 bytes of RAM.
The ram chip also serves as an I/O control and timer.  The entire board
including  a set of data switches, 29 key hex programming key board, and two
digit LED display measures 7" by 7".  Its made by a company called ACS.
The board is called a Micro Master 8000, PN#515030.  I plan on building an
expansion for it to operate an LCD alpa-numeric display.  I have also
thought of using such a board to make my own programmable ECU.  I would use
the same approach as Bosche's non sequential firing of the injectors.  I
don't think I'll mess with the interior of my Vanagon, but I plan to buy a
'70 to '74 Karman Ghia, as  project car.  I will keep the outside stock but
plan to ugrade the functional operation. 
     Have you seen Jameco's catalog? They also have it on-line at
http://www.jameco.com.  Their prices are not bad and they have quite a good
selection of basic parts.  
     I would like to hear from anyone else on the list that has an interest
in automating the interior of their cars.
I love gadgets, mabey thats why I became an industrial controls technician.  

                Happy New Year to all the List Members,  I enjoy every post,
and it saves me money too.!!
Colin A Moran

K&M Ranch
'86 Syncro GL "The Bronze Brick"