Yeah obviously a tablet would work as well. If using a touch screen though, I could use my vortexbox to run the app, or one of those little XBMC boxes.
I must be missing something.
Do you mean use a computer as your streamer, and use a touchscreen attached to the computer to control it?
Just not sure why a tablet would not be used instead?

In my system I use a tablet (iPad) to control my PC's foobar.
I also use the same tablet to control a Raspberry Pi (with Rune),
and to control my OpenElec XBMC computer.
While touch screens are neat, they are really just dumb tablets that need to be wired to the PC.