Raspberry pi ?

Hi,

sorry I'm not really a os "hacker" and I haven't even got the code yet, but was wondering if someone could help me with my issue:

Is there any activity of L4 on raspberry pi (a pocket size computer) ?   Or is there elsewhere I can ask.

Specifically the plan would be to build a ruby-machine on it. Single user but multi-process. If would only need to be able to access usb,ethernet and gpios. And run and start several ruby processes.
I know ruby vm well enough to cut that down to size. 

But I have no idea of how difficult it would be to remove linux and replace it with those 3 device drivers. Or even where to get those, how to integrate them. 

So i was hoping somebody here could say how crazy this is, or if I can stamp down some trodden path ?

Thanks

Torsten