I got my xbox working as a mythtv frontend while on vacation. I tried gentooX, grew annoyed and settled on Xebian as my distribution of choice. I am partially blogging this so that I can remember what I had to do to get everything working.
1) Installed modchip, a spider
2) Flashed modchip with 100% legal cromwell bios (I had to use a Memorex branded cdrw for the xbox drive to recognize it)
3) Installed Xebian (also had to use Memorex branded cdrw)
4) apt-get update && apt-get upgrade, you know the deal
5) Installed lame from source
6) Installed qt4-dev-tools w/ apt
7) Installed libtiff-dev w/ apt
8) Installed cdparanoia from source
9) Installed flac from source
10) Installed libid3tag from source
12) Installed mpeg2dec from source
11) Installed ffmpeg from source with ./configure –enable-shared –enable-pthreads
12) Installed libdvdread from source
14) Installed transcode frm source
15) Installed mythtv from source
16) Installed mythplugins from source