Both devices list Jazelle support, but enabling it is another story. I have also been told that Jazelle only optimizes operations that are already fast on the N770/N800, and that the speed boost wouldn't be much to write home about.

PhoneME Advanced is pretty fast as it is on the N800, it just lacks GTK support, and installing QT isn't for the faint of heart. Various people have been working on the GTK support, but I've yet to hear anything major. Hinkmond Wong specifically set up a branch to add GTK support in to, but it hasn't had anything past the initial commit (as of yesterday.)

I will absolutely tune in on this one. Can't wait.