I hate to sound like a shill
But bike hub store has some of their light weight hubs with 12mm rear and 15mm front. Brandon is trying to stock conversion kits too.
Front MTB Hubs
Rear MTB Hubs
He also stocks rotaz and I think he'd be glad to talk to you about them. He might even handle warrantee returns for rotaz.
Just give Brandon a call.
Brandon is very cool. I'd just give him a call and ask. I think you can get his number through the contact link on his site:
You can email him too. He usually replies pretty promptly.