There have been many attempts at making a decent tandem over the years, none lasted very long. There are too many issues with this configuration. But, if you can come up with a successful design, lots of people would buy one. Here is the last commercial attempt, which is no longer available: http://www.flying-hobby.com/shop/chi...ck-p-4694.html
. Personally, I think it could be done with two motors and two flybarless CP heads. Trying to cancel torque while retaining lift with FP heads doesn't work. You also need to drop the nose for forward flight, which is harder than it sounds, because the natural tendency is to lift. I think I've spent about 400 hours playing with tandem designs. I may try again someday, if I can come up with a better design.