Long rods for cast crank 225?

Yes, you quickly will be approaching the cost of aftermarket rods. Plus, don't forget after narrowing them, they'll have to be re-chamfered on both sides in the big end. So all those things almost make it cost prohibitive because you still end up with an inferior rod for the same cost or more than an H-beam rod.
That makes the assumption that K1/Molinar will do a run of cast crank long rods, as that is what this post was about initially