Steve,
Thanks for a quick response.
Sorry I didn't explain myself very well.
I have Nikon ED50 which I use on a Slik Sprint Pro tripod. This is a taller and more rigid version of the Video Sprint (which is not tall enough for me, and is too whippy).
However, the 3-way head is too jerky, so I was looking for a lightweight 'video' head. The head on the Video Sprint is 240g, which is the lightest I can find, but is not available separately. I was therefore going to try and find a secondhand one and transfer the head. Before doing this I wanted to make sure it could be removed in the normal way.
The only other thing I've seen is a 340g (?) Velbon PH248, attached to their CX400/480, but it's not available separately, and not removeable according to the catalogue. All the other fluid-effect heads I've seen are around 500g, so if you (or anyone else) know of any other lighter ones I would be very interested to hear about them.
Mark