Dunno if this might help....
I had a 2008 Trance X1. It once had a creaking noise too and it drove me insane. I did EVERYTHING. Pivots, BB, Shocks, chain, cluster, etc. In the end, the solution was so simple: Near the dropout, there is a grub screw, attaching the dropout to the rear triangle (see pic). If this grub screw runs dry, it will squeak every time pressure is applied to the rear triangle, e.g. pedalling, shock compression... Try removing the grub and lubing it with copperslip before putting it back. It worked for my bike!
