How is this different from any other pointing device? The only one I know where you didn't have to move your hand was the Touchstream LP (http://www.fingerworks.com/ST_product.html), but then typing was difficult at best.
You can keep your hand in home position for typing and manipulate the cursor. It doesn't actually move, but is force sensitive and is delicately calibrated to move in an intuitive manner.
With a Trackpoint-equipped keyboard and a Cintiq (or a tablet like the Intuos if you're using a laptop) you can rule the world. (Well, unless you're a gamer.) The only thing a Trackpoint can't do well is draw, and frankly touchpads, mice and trackballs fall short there as well.
EDIT -- I'm not certain you can find a keyboard with a Trackpoint that isn't part of a Thinkpad anymore. There used to be a couple of licensed versions in addition to the IBM-branded ones.
The thing that always infuriated me about these little nubs was not only do they tend to have very strange acceleration profiles, but they would quickly wear down from a smooth bump into something all jagged and rough, pock-marked like the surface of a meteorite. Track-pads just get buffed more shiny, from what I've seen.
My ThinkPad came with three styles to choose from. The original style, which I think you're referring to, did wear down after about a year. But it's easy and cheap to get replacements (and some backups are often included). The style I like, which is wide and flat like a mushroom top with bumps, doesn't seem to wear down at all.
As for the acceleration, like with any human input device, that's something you get used to, and it can be configured a bit as well.
I love my TrackPad. I won't buy a laptop without one. Unfortunately, these days, there are fewer and fewer available...
