There's an app in the Market called Silent Toggle Widget. It allows a full silent mode... but now that I think of it, I think Eclair offers full silence already.
And I don't know whether it would work anyway.
I'm in the same boat as you. That vibrate would wake me up every damn night. I finally just got in the habit of charging to 100% when I get home, then plugging it in in the bedroom before I brush my teeth. Now the vibrate happens before I get into bed. I know it's not a good solution, but it's the best I've found.
I just now noticed in my Sound settings that there's a "Vibrate" selection that has the option "Never". Does Eclair have that? Maybe that would do it?
Good luck! I feel your pain.