keyboard mux driver (straw man proposal)

dear hackers,

i'd like to follow up on keyboard mux driver discussion with some code. 
please dont start jumping up and down just yet :) this is a "straw man" 
code and everyone is welcome to beat the heck out of it.

basically the code is based on vkbd(4) and the idea that was discussed 
long time ago - create a "super" keyboard that consumes all other 
keyboards in the system. the code creates a "super" kbdmux keyboard. 
using new special ioctl's one can add multiple keyboards to the mux. 
then one simple switches the current keyboard to the kbdmux keyboard.

as you can see it is not usable from the kernel just yet, but i have 
managed to create a mux with two vkbd's and it worked (please see 
kbdmux_test.c program).

the questions that i wanted to ask

1) is this good enough abstraction for the keyboard mux? can anyone 
think of anything that would not work with this model?

2) should we decide to make this usable from the kernel, what is the 
best way to do it?

3) did i miss anything? please tell me if i did! :)

the code can be downloaded from

http://www.geocities.com/m_evmenkin/kbdmux.tar.gz (~7K)

i also put it in my home directory on freefall.

thanks,
max