try the Ibanez models (don't remember which model exactly)
or the 7 Strings Warlocks
I've heard that Washburn makes some good 7strings too, but I never played one, so I can't tell you.
probably the best thing to do is to go to every guitar store you can find in your area, and try every 7strings guitars you can. every brands, don't limitate yourself.
but it depends of your playing and what tone you wanna get, if you're more into prog, an ibanez would be good (and maybe get EMG's pickups..)
hopes it helps