Hence my first statement, and what DTZ said supports that. While at some point the force is usefully large, we're still talking about micro and nanotech here. And to the vast majority of the engineering world, that's alien talk.
Add the fact that micro and nanotech is still under development and you realize my lack of enthusiasm. Like I said, there are at least two other ways to levitate MUCH larger objects, at least one of which is already in widespread use.