Also since Frodo is 320x200+borders it would make sense to have pixel doubling enabled at least in fullscreen mode. Too bad Xsp nokia extension is unstable by design (you can't turn pixel doubling off quickly enough if system pops up some dialog ==> screen is messed) . I have somewhat working version of SDL Frodo build with pixeldoubling enabled via Xsp.

Best would be to write some generic code snippet to update screen via framebuffer ioctl like mplayer does it. One could just add such code to project and replace SDL_UpdateRect with such call. ioctl has non-sticky pixeldoubling flag valid only per specific screen update so it will not mess the screen.

Regarding the on-screen keyboard - than would be really nice. If you could code it in modular way so is can be used as a filter after calling SDL_PollEvent (i.e it would translate SDL mouse events to sdl key events) it would be really great and reusable also for many other sdl based projects.