I can't give you a firm number on battery life, either, but I can say that my new Tungsten T has significantly shorter battery life than my old, venerable Palm V.
I once took my Palm V on a trip to Europe, and used it quite a bit, and after two weeks the battery meter was just under half full.
My new palm, on the other hand, would probably only have lasted a week under the same workload, if even that, without using bluetooth.