Did a little more playing tonight with some time lapse shots. All very easy when the moon maintains a constant magnitude, but not sure if this is viable during a total eclipse. I stacked the individual frames in CS3, and then calculated the stack maximum to produce the composite images. No cropping, but they have been downsampled for flickr. Links to the images are below. They are at 70mm, 200mm and 400mm respectively on a 1.6 crop DSLR. As they are just test images, please excuse the framing, cropping, and the odd wonky moon!
A few more tips I've picked up.
If it's going to be cold, put a lens hood on your lens if you have one. Not so much of an issue when you're pointing the lens up high in the sky though
A tripod that allows the head to be mounted at an angle is very useful once the moon gets up high in the sky.
It can be useful to align the horizontal motion of the moon with the panning axis of the tripod head. This makes it far easier to track and pan as the moon moves.
I found manual focus much easier - it saved the hunting especially when the moon was started in one corner of the frame. It can be a little tricky focusing it initially with a small viewfinder, and the moon being small in the first place with a normal telephoto lens.
You'll probably want either to lie underneath the tripod if your camera isn't that far off the ground, or a chair if it is higher up. You'll have to get your head underneath the screen to check, unless you want a laptop outside with you. An angle viewfinder may help a little for framing and focusing, but not with reviewing pictures.
I've preferred to capture raw rather than a jpeg - hopefully when the magnitude starts changing it will provide more latitude for adjusting the exposure if it needs to be placed next to others in a montage of the eclipse.
Cheers Gav