The excellent BJNichols is saying that you don't need a power adapter in the newer cameras to lock-up the mirror for cleaning. The D70 for example uses the camera's battery to lock-up. Just check the d200 manual to confirm this feature. There should be a pdf of the manual posted on the web soon.
We'll have to see a manual to know for sure what the D200 lock requires, but the D70 indeed can be locked up for cleaning using only the internal batteries. I'd bet the D200 will work that way too - Nikon surely has sympathy for folks who may be far away from an AC outlet and need to do a sensor cleaning.
Nikon and others have recommended AC adapters for cleaning to reduce the risk that someone might have a battery run out during cleaning and trigger a disaster. The new battery monitoring circuits of the D200 should make judging battery charge much more accurate. Until we see a D200 manual that indicates otherwise, I'd hold off getting the AC adapter just for cleaning.
I've taken at least 100,000 aggregate exposures with my D100's, D2H, and D2X and I have yet to "clean" a sensor. I have purchased everything that I need to do it including the power adapters. But I have not found a need to do it yet. Every time that I have noticed a large dust bunny on the sensor, I've been able to "blow it off" with rocket blower. I do a lot of lens changes in the field. And I'm sure that my sensors could be cleaned, but there are not any large dust particles on them right now and the small ones are not noticeable on the fast majority of my images.
For those of you who have not yet entered the world of digital, you might be pleasantly surprised about how little dust is a real problem on your images, even on a 10MP camera.
I agree with you that dust isn't the problem it's often made out to be. And doing a thorough wet cleaning is a lot easier than it sounds. I find I need to do a spot-free cleaning perhaps thrice a year.
But to safely use a blower you would need to use a cleaning mirror lockup mode. I don't like the idea of using "B" since it powers all the sensor circuits.