The touch screen thing is what has held me back from updating to Windows 8. Big touch screen monitors are expensive right now, and all-in-ones tend to be slow. I don't want to give up a 25" monitor to have a fingerprint-encrusted 17" screen.
What might be more feasible for testing, and a lower initial cost would be a wireless stand alone touch pad.
I suspect there might be more people who have updated to Windows 8 but don't have a touch screen yet. Such a peripheral might be even be useful for your kiosk - bigger screen and save money; you'll just have to secure the pad to the kiosk so somebody doesn't accidentally leave with it.
See one of these for instance:
Have we discussed my consulting fees lately?