This is close one of the motivating use cases for VNC if recall correctly: touch screen office phones (over ATM I think). Instead of making the phones smarter and adding/customising buttons, just thin-client them all with resistive touch screens. You'd have a controlling box already on site (PABX or whatever) and the the deployment would be homogeneous per site. Right until entirely softphones replaced them, all the office I worked in still used awful WinCE or whatever local OS even though they spend 99.9% of their time doing nothing or just showing call progress. Strange it didn't catch on (anywhere I noticed I mean!)