SEC was based in Seattle and some repair dude has all his old inventory. Don't know how helpful that is, since I seriously doubt they have any 7 string replacement necks you can buy. But since that's local to you you could always inquire and (politely) be like, "Yo, my SEC kind of sucks, Washburns fault, maybe you have ideas on how to fix this".
RJW Guitar Repair
Don't think the original inventor is still affiliated with the brand, I think the IP now belongs to Washburn. The dude on the linked site was the guy under SD and he mentions doing all the warranty repair work for Washburn's models.