I would assume that you are talking about ITRON (which was featured on slashdot on the 19th). It is not based on linux in any way.
There are RTOS that are designed for the pic. Here are two that came up in the first two pages in google:
http://www.testech-elect.com/hitech/salvos.htm http://www.realogy.com/realtime.shtml
It would still take a lot of work to port the IFI stuff to one of those RTOS.