I've never seen it. Look for reviews. The way it's described I'm afraid it's for birding scopes and not cameras.
Fluid designs make a lot of sense and I know of some people that have done it, but with big, video heads that cost over $1,000.
Of course, you know that I've gone to almost 100% hand holding. I use my tripod when I'm going to focus on one subject for a long period of time and I don't expect a lot of movement. The tripod gives my arms a rest.
I use the Arca-Swiss Z1 ballhead (which is also great for scenics and meteor shadows) combined with the Wimberley Sidekick, a combination that I highly recommend.