I thought i had replied to this yesterday, anyhow :

The problem IMO is the stream post if you have not fix that already. If not, take it out, find a large bumper sticker made of vinyl or maybe a PDA screen protector. Cut a piece like inch wide and maybe 4 or 5 inches long and put that in the back of the seatpost. Put tiny grease in the vinyl too and put it back in. That will take care of the creack. If the creak comes back u know what to replace. I have a BMC just in case.

Options

- put some oil in the front quick release mechanism or replace it.

- Put some grease between the fork spacers.

- Put some oil between the chainring and the bolts and tight them again.

- Pedals, put some oil in the pedals bearings, have seen this aswell

- Oil in the streampost bolt wedge thing, if its dry i could start creaking.

Good luck