Well, maybe when I can find some time, I could manage something.

*In previous years I have developed virtual keyboard for linux
*in current project I have implementing message sending and receiving

So 2 solutions I could propose:
*port my virtual keyboard and activate/disable it with power button
*write SMS application for portrait mode

However, you would have to wait at least a month for it, I have no time currently to do any of those

I should not even be checking this forum, damn it!!