Well I think I've repeated myself too much recently, since there are so many news that touch the topic. But see http://wiki.openmoko.org/wiki/User:TimoJyrinki for a few screenshots of my Debian setup. There are several other people with different setups. The key thing is that it's possible.
With FSO2 now in Debian, there are modem drivers and eg. audio setup support for several other smartphones like Palm Pre, Nokia N900, some HTC:s etc. oFono is in Debian as well, but I haven't checked that out and it's only the modem part.
There is near zero productization. At least with FreeRunner you have a packaged kernel in pkg-fso team's repository, but for others you need your vmlinuz + modules from somewhere, in addition to Debian ARM rootfs. And you need to setup the UI like SHR software manually. But it's just about missing for example install.sh similar to what FreeRunner has, or proper Debian kernel and debian-installer support, or offering pre-configured rootfs:s. And doing more of the needed packaging work.