Hey.
I know a good bit about the commencals, they tend to crack a lot because the alloy is slightly too brittle. You can feel it when you face the disc brake mounts and BB.
Santacruz, Kona, Specialized's alloys are all about 20 to 30% softer infact all the frames I've tuned except for the pinnacle frames are softer in terms of alloy.
Rather than flex very slightly, they tend to crack and snap over time. Their bearings are also not very good, once they sieze up you will be putting a lot of pressure on the back end and subsequently the front as well.
Most of the time it's the front end that snaps, the head tube, upper shock mounting brackets and lower seat tube. So there is a good chance you can get a new back end off ebay.
If you look back to 2003 when santa cruz and orange where still developing their light freeride, freeride and DH bikes, they both introduced the same top, head, bottom tube gusset.
I doubt it was just for looks as the older bullits where prone to snapping where the commencals do at the head, top, bottom tube join.
I could more likely than not source you a snapped frame, all you do is take the bits you need and resell the rest.
There's a rider over in france that I'm trying to get a frame for just now, he had a snapped commy, I could see if he will post the back end over for you. It was 2 weeks ago it snapped but he might still have it.
Cracks and snapping / rubbish bearings aside, the commencals are very impressive in terms of handling and I would rank them with my other favourite 5/6" frames of all time spec enduro 03/04, giant VT spec end 05=.
Gotta go my mate has a busted mech hanger on his norco and he's of tomorrow for some DHing. If we can sort it.
ridefree!