If you're serious about 8string guitars, you have to check out two British Luthiers, namely Hugh Manson, www.mansonguitars.com (I think)
and Doug...umm, dunno Dougs surname,but he makes Blackmachine guitars...
www.blackmachine.net
Black Machine are amazing guitars, I've played one or two and I lovge them...they're pretty pricey, but worth it, if you want it...he even makes a fan-fret 8 string.

check them out.