As mentioned in my profile I am an avid Amiga fan and have been heavily involved in the Aros project which is an open source re write of the Amiga OS3.1, it is in a very usable state now and is way more advanced than Amiga OS3.1 but is designed to be source code compatible rather than binary. It is available on x86, PPC, m68k and Arm.
Anyway, I intend getting this ported to Rasberry Pi and drivers written to fully support it and would like to hear from any people that would like to see the Amiga operating system fly again on $25 hardware.
I will keep you all updated, probably more so when hardware is available.
All the best