is the hose routing stopping the "upside down" mounting? there would be other reason to not mount the caliper inverted, other than needing to sort out mounting bracket issues...

a short, J shaped, custom-bent/flared metal tube using the correct fittings will solve the hose routing issue, i'd think.. tube bender guides and flaring tools are easily obtained.

Bleeding the caliper would require removing it from the bike and suspending it, bleeder-up... Heck, that works better anyways!