I am thinking about this with my '06 Fatboy as well. cost looks to be between $325 for Harley controls to as much as $800 for some models. Not wanting to screw up the the brake cylinder will probably have an Indy install them for me.
Put forward controls on my 00 FB. Loved 'em. Thinking about doing the same to my King. Either that or buying the brackets that move the floorboards forward 2 inches...haven't decided yet.
I switched out the floorboards on my o7 fatboy, with the forwards off an 07 night train. I love them, look great and super confortable. I think any forward will work as long as they are around the same year ( if switching from another softail) I got mine off a member here. Only paid about $200.