so ive been thinking about the n9's low-power-screen and seriously considering exploring an arduino lcd TOH, but i forgot that im obviously never going to use anything other than a keyboard other half.

which led me to thinking about a kb+lcd OH pipe dream. can anyone here comment on the feasibility of:
1) making an lcd OH at all, preferably 16x4 with backlight control. {i2c is way faster than LCD refresh rates, right?}
2) making a kb OH which when closed, would be disconnected, fully exposing the i2c interface and power for a generic addtl OH.
3) actually making a combined kb+lcd OH. is there sufficient bandwidth on i2c, sufficient power, etc? is it extremely unlikely that a microcontroller exists that can handle this? will the thickness be ridiculous? etc.