I am currently building a clubman (Lotus 7 replica) that is to be powered by a Mazda RX8 rotary engine. Due to the size of the vehicle and emissions requirements I need to use the RX8 electronics but cannot fit the standard instrument cluster. Plus an instrument cluster from another vehicle wont work because the RX8 uses a CAN bus setup that is incompatible with most other clusters.
So I can do one of two things, add analog sensors to the vehicle to drive aftermarket gauges or develop a carputer that IS my instrument cluster among many other things...
I work as a software developer so I chose option B. I've started a blog detailing my progress of the overall project and thought that people here might be interested :-)
I've begun development of a carputer that runs Windows XP with software developed using vb.net. I purchased an OBDLink that allows me to send OBD-II requests as well as listen for data on the CAN bus.
Full details can be read here: http://lukesclubmanbuilddiary.blogspot.com/. There are plenty of pictures and even some video of the digital cluster in action (running off OBD-II while I wait for my RX8 electronics to arrive).
Some sample pictures of the dash (more on the blog):