I know this is a big tabu in the world of Apple( we just like to use our fingers) but think of this as part of the evolution to a true touch screen.
The makers of the iPen for you iPad have a new project called iPen 2 for the iMac. The iPen 2 is will have an iPad model as well, but as you have probably guess by now the iPen2 lets you write directly onto an iMac or Apple Display with glass panel and is compatible with every application in Mac OS and Windows. The iPen 2 is pressure sensitive so you can control your strokes easily, while letting you write or draw directly on an iMac screen by using a of sensors that attaches right to the iMac display.
Cregle(The Makers) says that the iPen2 is angle agnostic so no matter how you hold your pen it will still write accurately, and it’s lightweight inking so you don’t have to press really hard into your device to make it work. The iPen 2 takes 75 percent less weight to generate inking than the iPen 1. The sensor system, for both iPad and Mac, uses two different invisble light sensors that triangulate the pen’s location on the screen, which is then transmitted to the Mac, making a digital pen that works across the whole screen. The iMac model iPen 2 stylus for Apple display will go for $169 and the iPad model for $119.
The iPen 2 is a Kickstarter Project check it out here.