what tonal specs are you after???
also dont believe to much about tonewood descriptions on the internet, alot of them are false... liek they say zebrawood is similar in tone as maple, NO FUCKIGN WAY...
it try to get some limba, it works realy easy, and nice ballanced tone, plenty of low end and doesnt need a top to get the highs like mahogany needs...
zebrawood has some nice lowend, but its kindof muddy, great for jazzy sounding uitar, but they sortof lack definition for metal.
personally id sayno to mahogany, muddy stuff unless you get a proper piece, also, its realy hard to get proper mahogany, you want honduras, NOT sipo, sipo is cheapo, but since most people confuse the 2 alot of mahogany is selled as honduras while its sipo.
just liek alot of swamp ash bodies arent made of swamp ash but regular light ash, most people at woodcompanies cant recognise real swampash from light ash, also, about every body ive seen on warmoth.com thats supposed to be swampash is just regular ash. so be carefull with that
bubinga has loads of lowend, and its also a realy tight sounding wood, should work fine for a 7 string i guess, its heavy as fuck though
personaly id try to get some limba, its plenty available, its not too expensive, its lightweight, it should have plenty of tone, and you can usualy find nice 1 piece body blanks without to much trouble... if this is your first body you might try to get a 1piece blank, cuz gluing 2 body part together properly will take you some (expensive) tools and alot of practice to do properly... i know from my own experience