The swingarm would need to be braced. They aren't rigid enough to have the shock all the way up front. Plus the shock would need a different spring, possibly revalved to feel right. The r6 shock is set up for a 2:1 ratio, 2 inches of wheel travel is 1 inch of shock travel.
Simplest is use a swingarm and linkage designed for a mono shock, and just build an upper mount. Or figure out how much bracing you need, and be ready for new spring on the shock.
I'm using an fzr400rr swingarm, a US spec fzr400 swingarm would be skinnier and not as bulky.