Are you just butt-sure you've pinned down the location correctly? Something you've done should have worked.

If you're sure . . . how are you sure?

Has anything you've done made any diff?? You said spit worked temporarily. Did the grease?? Did you clean the seat tube with a rag relatively soaked in something like WD-40 (or ~) until spotless inside??

When do you notice the sound? Sitting? Hammering up a hill? Whether pedaling or not? When the bike's in the other room??

Might be/could be/oughta' think about looking south . . . toward the bb/crank bolts/chainring bolts/etc.

Check this $hit out:

http://www.parktool.com/repair_help/...queaking.shtml