I like seven-strings, I totally see the point - it's not just to get a few lower notes, it's what kinds of things you can do up the neck. However, the strings are just barely working on a seven, as far as keeping a really good tone and not wavering in pitch and not sounding "thuddy." - IMO :toothy11: I have a 25" scale Warmoth 7, and 25.5" and 26.5" scale Schecters. About the only way I could see an eight-string work for me is if it had the fanned frets, which Rondo is doing.
I wish Warmoth would put more variety into their seven string offerings, because I spent some time over at the seven string forum when I was "gearing up" and there's a whole lot of people who want something other than "wizard" neck thicknesses. Right now, the only choice is Schecter or megabuck custom guitars. I suspect Warmoth makes their seven string necks with a 25" scale so that they don't have to make another trussrod, but if they were to offer 26.5" scale seven necks with a boatneck or '59 profile, there might be a big surge - leading to more attention to the eight string potential. Since the time four years ago that I was looking, Schecter has been doing great business with their fat neck sevens.