The laser cut idea is like having a 104mm bcd bashguard on the outside, but with an extra set of 64mm holes that you can bolt the inner chainring to, with very long bolts and spacers. You have to rotate the holes so that the flange and crank arm doesn't get in the way of the holes. Laser cutting is maybe $30. You have to make a dxf drawing to a laser cutter provider. They supply the metal plates on their Automatic cutting machines