I designed something similar for a pier I built for one of the imagers on this site... You can see the 3d rendering here:
http://i858.photobucket.com/albums/a...ase%2001_1.jpg
The pier footprint can be seen here:
http://i858.photobucket.com/albums/a...ype%2002_1.jpg
Note how the load is directly coupled via tensile or compressive elements (no potentially flexing plates)
And the finished pier (for an AP1600 + Honders) is here:
http://i858.photobucket.com/albums/a...Milne/pier.jpg
I made some footings for 40' shipping containers using a similar design out of 304 stainless, driven in to salty clay. For an experiment I released the jacks with only one footing installed on a single corner to see what would happen. The single footing held approximately 4 tonnes (plus a fair bit of torque). The laser level indicated that it settled approximately 1mm.
It works.. and is a heck of a lot easier than concrete.