I just finished putting a dual disc set up on my FXDB. So far I have less than $150 in it. I still have to get a new braided brake line but I used one from a road glide until I get the braided line. Here are the parts I used:

Fat Bob right side slider
Right side caliper from a touring model
classic black floating rotor
11/16 master cylinder from touring model

The only part I bought new was the rotor and I found it on ebay for $75. The rest were take off parts that I scored from a dealer or from ebay.
The only thing that doesn't line up perfectly is the fender tabs on the fatbob slider. But all you have to do is drill a new hole and you've got that handled.
Keep in mind, this is using the 07 and back touring caliper. Or you could simply get the right side caliper from a fatbob. The touring calipers are readily available for cheap on ebay. I was lucky enough to have a friend with take off calipers from his road glide.

 

more pics

 

All kinds of dark details on that ride; looking good...

How do you like the Metzlers? I can't get matching Bridgestones anymore; may use Metz's next tire change...

 

The metzlers are ok. Think I'm gonna go back to Avons next time. I've used metzlers for a while but I bonestly think the avons are stickier.

 

Looks good. Your bike and sickwithit bike is the reason I joined this forum. Wish I could find someone that has put a old 18x5.5 V-Rod rear wheel on a dyna as I want the Duel disk with matching rims but don't like spoke wheels and don't have $2400 for a matching set of after market wheels.

 

Outstanding! That is the mod I hope someday to do.

Maybe you could do a step-by-step for those of us who endeavor to such?

 

That is bada$$ dude ....the badest bike on the forum .

 

Nice work man! How is the skinny front tire handling the extra stopping power?

 

That is nice, I am kicking myself for not going to dual discs when I ordered my new wheels.

 

Looks good! Did you use the standard FXDB slider on the left leg, or did you swap both sliders out for the FXDF sliders?