I don't know if you use Growl but it's pretty versatile. You can choose the place where it pops up, the type of notif. (even speech or mail - not that useful for TM), the icon, how long it stays, etc. on per command basis (even over a network). So it can be used for notif. of background tasks as well for "instant feedback on the command executed".
Allan
I think you use this discussion list as a user feedback collection point. In which case, FWIW, I would be very glad for Growl support too for the reasons stated above. Growl is highly configurable, usable in a persistent, immediate and coalesced modes and very OS X. I find tooltips fiddly and non-persistent. I use most text at 14 points and I find tooltips bothersome to read.
cheers David.