I think his relationship with Washburn has been slowly decreasing since the Randall amp he released back in the mid 2000's. There were tons of tales of reliability and availability issues. I played one back in 2009-ish and it sounded exactly like a DSL with a rat boosting, well, until it quit working mid play. When I informed the guy at the shop that it had sputtered out, he shrugged and commented that it was the second amp they had to send back in two months.
I was also under the understanding that Washburn had exclusive rights to the Stephen's Extended Cutaway system, but from what I am seeing I don't think that is the case. A Nuno guitar without the stephen's system just doesn't seem right, so I am glad they are able to use it on his line.