since he's running mavic ellipses respacing/redishing isn't going to be the solution.

If you were using a regular crank instead of outboard bearing one, you'd just need a new BB.
Don't the outboard bearings push the chainline further out than a regular road double, with no way to adjust?

which direction is it off?
too far out on the chainring end?
if it's no there already, put the chainring on the inside of the spider, and use chainring spacers to move it in further if necessary. It'll be butt-ugly, but it should work.
or get a new crank.

(don't the mavic ellipses have a strange chainline too, 45mm I think?)