Bumps, eh?

Q/R tension? Schmutz in the dropouts? I had this not too long ago.

Also, have you greased the Q/R skewers?

Pedals and seat rails also come to mind, but I think you said you looked at those (this is a long thread, so forgive me for not remembering every little detail).

<creak, creak, creak> <= sorry, couldn't resist...