Some changes might be needed to optimize the layout (default to fullscreen windows, merged menubar/toolbars (we need a standard toolbar class anyway)), and even more if you intend to target devices without touchscreen who use a joystick-like HID, but I think primary targets would be PDA and PDA-like smartphones.While it's not a standard, last year I spawned the libwalter project @ OSDrawer to gather together BeOS code that was floating around the WWW which would make a good starting point for classes for R2. MIT license, OT style guidelines, and a jam-based build. A toolbar class is part of the project. I had envisioned someone examining the code for R2, but while I'm not saying any of it should be part of R1, I wouldn't complain about it, either. :)
As I said already, touchscreen are just a special kind of tablet that have absolute coords that match pixel pos. For devices not having a touchscreen, The joypad can emulate arrow keys, and I already started writing a T9 input method. I also started a pen input method that can serve to incorporate an handwriting recognizer.I shall commit those to svn, I need versioning on that too.