You could check out windriver RTOS and their VxWorks suite. It has support for CAN built in as well as Tilcon graphics suite. I have spent way to many hours researching this exact same thing about 3 years ago but times have changed and I do believe that is more feasible now than before.
http://www.windriver.com/products/platforms/automotive/
also check out palmerperformance.com
Carter