I think raising a dishwasher is a great idea. More power to you!

Bringing it up even 12 inches is enough to relieve your back. Bringing
it up to counter level would make you reach for the top rack, so I
wouldn't advise that. Remember, that the higher you raise it, the less
usable the space on top is, that is if you aren't sinking it into a
wall of other things.

One alternative is to get a single drawer dishwasher, or get two and
place on either side of the sink. This solves the reach over problem.
They are very expensive though.