I still have some ColdFires in an embedded product of the company I work in. The biggest chips even have a full-blown MMU built in. Can be made to run Linux (2.6.x.) just fine, but the toolchains (e.g. gcc) seem to have somewhat bit-rottet, unfortunately.
I was using (two years ago, the last time I played with them) a freescale provided 2.6 kernel that just hasn't been upgraded, and the old mentor-graphics/code-sourcery tool-chain. Together with busybox, I was able to get a basic serial console-based system with shell, all rather straightforward.
I didn't succeed getting a newer gcc+newlib compiled for m68k, though.
All in all, the whole ecosystem around m68k seemed to have rotted away, also m68k support was also taken out of u-boot at some point if I remember correctly.
While it certainly would be possible to fix all of this, it's just too much effort "just for fun" with no particular gain besides "because I can":
If you actually have the need for some embedded CPU, one is much better off using whatever ARM core the majority of tinkerers is currently using, that way you are less likely to experience this bitrot.
