On my aging 939 ST20G5 I've added a front panel display (iMON), bungie'd the drives and replaced the hex mesh on the back with a wire guard. I never got round to posting a project log though, as its been a gradual thing and I've still not quite got round to doing the finishing touches.
The most common mod you'll see on older shuttles is room for a double space graphics card by cutting out the edge of the case, but that sounded a bit too demanding for me!
PK!