I'm no expert, but as far as I know, Gentoo requires a lot of memory to be able to compile new packages. If you had access to another machine that could cross compile the packages for the architecture, and the hard drive space was large enough, a port could be feasible, but I think Gentoo has too much overhead for your needs. Probably far better (and easier) to try a more minimal distribution that targets machines with low amounts of ram. Debian has successfully been ported to embedded architectures on commercial devices.