From the looks of it you can still use your Bluetooth keyboard as it is with the Linux bluetooth stack, except you have to figure out a way to power it .. yet a

From the looks of it you can still use your Bluetooth keyboard as it is with the Linux bluetooth stack, except you have to figure out a way to power it .. yet another battery? I think you can just create another module that'll split the gpio to keypad and other purposes as it is just a USB keypad..