So. A friend of mine did the gambling for me, and surprised me with a 7” Lilliput touchscreen USB monitor. I am typing on it with the stylus taped to my fingers, because otherwise I lose my grip after a while and the pinching motion hurts.
If you want to use this device on something other than your home computer, be aware that the monitor requires driver installations for the device and the touchscreen capability. The disk includes drivers for 2000 through 7, 32 bit. Installation is straightforward, as is the touch calibration – you hold the stylus on 4 points until it says OK. You can also choose 9 or 25 points from the calibration menu later on, and there is also a draw test to determine accuracy. You do need some degree of fine motor control.
The resistive screen is sensitive, but not too sensitive. The most I have to watch for is an accidental double tap. A tap on the screen produces a left click, and you can adjust the double click speed in the settings. There is an adjustable auto right click option, in which holding the stylus on a point produces a right click. My fine motor movement can be shaky occasionally, so I am trying to find a good interval.
To use the screen as an input device, you have to click the monitor icon in the taskbar and select Mirror. In order for the touchscreen to act as an absolute mouse, it has to lower the resolution of your larger main monitor. You can increase the resolution after, but then your click targets will be slightly off. The scaling hasn’t generally been a problem with major websites, but there may be the occasional site where the sidebar is cut off and there’s no horizontal scroll. In those cases, there may be links for skipping to the sidebar. Your original resolution is restored when you turn off the touch monitor.
The only thing that you might have to mess with is your onscreen keyboard, especially for long writing. If you want to see the rest of the screen as you write a document, you will have to keep the keyboard very small. I decided I couldn’t write on this with a conventional onscreen keyboard at all, and am using the free Dynamic Keyboard (which is purely for spelling and is well suited to touch devices). The Dynamic Keyboard deserves its own post, which I will write shortly.
Hand to Mouth: Assistive Technology 
How is the screen size for you? I am pining for a touchscreen device but won’t invest until there’s one that I know can do everything I need (new apps for the iPad are pushing it up in my estimation).
I had to set the touchscreen as the main monitor, instead of Mirror, to be able to use the entire screen. The screen size isn’t too bad for most things, at least related to reading and (with the right keyboard) writing. I can read about 12 point comfortably. I do have trouble hitting the scrollbar and arrows consistently, as well as really small links or icons. That might just be me. Average buttons and icons are easy, and I can change the font for the links.
It REALLY doesn’t like it when I play a DVD, though; it freezes or goes black, and makes it impossible to exit Media Player. So for that I turn it off and use the large monitor. Hulu plays, but slowly.
I know what you mean about the iPad; if I had the money I’d be tempted to get one.