I THINK some guys have used a SX fender (comes in orange too!). A single disc is all you need. Measure and buy a new steel braided brake line for the left side of the wheel and lose the right caliper.
If you must keep both calipers then I think will probably need two new brake lines and I would go with a different set up at the master cylinder to make it work bitchin'. You can set it up so both lines go directly to the master cylinder so there is no "t" in the line, giving you more braking power, although, like I said before you dont need it....
PM surfphoto he has his 05 set up the way you want yours.
I am usually drunk when I post so dont take it personally !
2012 KTM 990