Honestly don't know if this has been done before--I did a quick search of the forum for "laser" and mostly came up with posts about show lighting. So, anyway, why not add a small laser unit to the front of each cabinet? Small switch and two AA batteries and suddenly positioning the cabs becomes effortless. Or maybe it's over-thinking things, not that I've ever been accused of that.

http://www.fasttech.com/search?laser
So, if using cabinets in a vertical array, the bottom one should hit maybe the third row...top one should hit the back row (or whatever)...but I have hard time feeling confident that my "eyeballing it" is really good enough, so I end up fiddling with it more than I really ought.
Anyway, just a thought.