Seems Microsoft is moving to finalize the renaming of Live Search to Kumo, according to LiveSide.net. The possibility has been discussed at various times this year.
Renaming and branding moves by search engines have not had much luck. Ask.coms removal of Jeeves seemed to hurt them, FindWhat and eSpotting merger and rename to Miva definitely impacted the companies, so there is data for not making the changes.
True GoClick to Overture went okay - but then they had a great product in a growing market - just like BackRub and Google.... but that was really prepublic launch.
If the move goes through will be well worth tracking.