As for having an opposite double neck guitar for ambidextrous playing , I've tried left handed guitar before (I'm right handed) , and I know I wasn't that bad in my fisrt day with guitar so I dumped the idea , plus it's worthless other than showing off , which you can do with lot's of other tricks ... I mean what are you REALLY going to do with it ? You can play more effectively with a sequencer or something that plays back ... or with another guitarist !
Even Michael Angelo himself never used it for recording , he just show off live with it.
Before throwing your money on something like that , try playing your guitar with the other hand , don't bother flipping the strings and try to play some chromatic exercises , just to see if it could work for you.
So what's a "war guitar" ?