Troll Touch has been in the business of slapping touchscreens on Apple computers for a lot longer than you might expect (since 1987), so if nothing else, you can rest assured that they’ve done this sort of thing before. The touchscreens in question fit the new 21.5” and 27” iMacs, and are resistive. They can be purchased as separate overlays with USB controllers, or can be installed by Troll Touch. Troll Touch is an Apple authorized service provider, but if you need to send in your iMac for repairs, you’ll have to send it to Troll Touch post-installation. Not that that super-slim iMac is actually capable of being repaired.
Purchasing the touchscreen and installation from Troll Touch will cost $1,000 for the 21.5” iMac and $1,400 for the 27” iMac. So, you’re going to have to really, really want a touchscreen to capitulate to those prices, especially considering these new, ultra-thin computers aren’t exactly built to last.