There are a lot of options out there when it comes to SFA swap for these trucks.
Here is a link to the route I went for my SFA this is one option out there just to give you an idea of how I am doing my build.
http://pirate4x4.com/forum/showthread.php?t=952418&highlight=triple+dmax
Here is a link on this forum of another route you can go
http://www.duramaxdiesels.com/forum/showthread.php?t=36574
First decide what you want the truck to be used for and how you want it to function.
Second decide on what your new ride height is going to be. Most times it is very hard to achieve factory IFS ride height with a SFA.
Third decide what type of suspension is going to locate the SFA.
Examples: Leaf sprung, 4- LInk, Radius arm, these would be ideal for being able to drive on the road as well as off road. You will also want to run a track bar to locate the axle side to side with any setup you use.
Crossover steering is a must have unless you are wanting to do some severe rock crawling and want to go full hydro steering. Crossover steering with hydro assist is a great way to go for running on the the street and off road but there is some cost involved.
If you decide on a link setup or radius arm then you need to decide do you want to run Coilovers or Coils and shcocks seperate from each other.
Now with that all being said the single most important decision is what front axle to use. I would stay away from the dodge AAM front axle and and personally would not use a balljoint axle prior to the 05 and newer SuperDuty axles. The 78-79 Ford F250-F350 Dana 60 are one of the most popular becasue they have the king pin setup and come with a High Pinion. Kingpins hold up alot better than a balljoint.
ORU makes a leaf spring kit that has the brackets and shackles to run leafs on the front. This would by far be the easiest kit setup to do and the cheapest.
If you want to make your own stuff and not by a kit it will be some trial and error. Once I finish the 4 Link front and rear on my big truck I want to try and get the entire front frame section from a Ford Superduty 05-up and use the factory radius arms, springs, brackets, trackbar, shocks, axle, etc... And swap it onto my DD dually Dmax and see how well that will work.
TONS of options out there your Wallet and your Fab skills will decide the route you go. Be smart do your homework and ask lots of questions. Don't be afraid to call these kit builders. If you go with a kit you will want someone that can talk you through the hard parts over the phone.
Toby Lavender at Triple X Traction is a great guy to tlak to if you decide on going a 4 Link setup.
Best of luck keep us updated!