Ior give Andy Goring/SumpUK a shout.
This is the route I would go. I am currently diving an XDeep Stealth Tec but have been looking to get away from XDeep even though I love mine. I am 99.9% sold on Andy's sidemount system and his new hardware is incredible. If you haven't seen his Quick Connect hardware that requires no threading onto the harness, give it a look.