I haven't seen much on this topic but there are people out there who have put an electric clutch on their existing power steering to save energy for highway driving.
http://ecomodder.com/forum/showthrea...ing-14952.html
And there are also aftermarket columns with electric power steering too. Lookup EZ power steering.
There are also some Saturns out there people have been yarding parts from to retrofit electric power steering.