Doubt it, at least until Apple decides to let us connect a Bluetooth keyboard, or provides some other alternatives for keyboard input. I doubt anyone will bother with this kind of app. Of course, I've been wrong before
There's definitely a case for providing this functionality. Apple would be crazy not to support it, perhaps once they get over their initial phase of promoting it as a media device they will begin to expand it's options a little.
If you want to use your TV for Word then just hook it up via a HDMI adapter to your computer. Starting with the failed WebTV of years ago there is a reason that having a web browsing on your TV via media player doesn't ever catch on ... because the experience sucks! Word on your TV would be no different. A TV is a different tool than a computer, and a computer is a different tool than a tablet/phone. I know there are those that think that eventually all these things will coalesce with common OSs but so far Apple, Google, and Microsoft have failed at all attempts.