Getting the doubler does seem like the best option for this rig. Cheaper than an atlas, will save my clutch, and not have to re-gear. Taking on such an endeavor is scary to me as it is completely unknown territory. Getting the shaft/plate made, doing the linkage, how much shorter the drive shafts need to be, and what to cut off the extra case is the parts I will have to learn about. Things unknown, like does the gas tank have to modified for it? Do I have to lose the full console for the shifters?
I have found that just reading how to do mods is not the same as actually doing them. I will always learn/retain more by doing, than imagining doing it. I would definitely need help from someone that has actually built and installed a doubler to take on such a Mod.
The first step is to figure out what you want to use as a doubler. Bolt pattern and ease of building/mounting should be the first priority. What pattern does your 1354 have? Is it the same or different than the usual Ford 6 bolt circular pattern? Its probably different, cause I think??? only fullsize trucks have the 6 bolt circular. So if you go with a fullsize case half to use as a doubler, you will need another adapter to mate it to your trans.
If you use a 203 you will have a 4 speed doubler, (doubler gear/case gear) low/low, low/high, high/low, and high/high, because a 203 is 2:1, and the 1354 is 2.6?:1.
If you use another case with the same ratio you will only have 3 speeds, because with 1 in high and the other in low is the same no matter which is in low.
Don't worry about your new driveshafts until you get it all built and installed. Measuring for, and getting new shafts built is pretty easy. That being said, don't forget completely about them. Just use a broomstick or something as mock up, to make sure you have clearance and aren't hitting something, for shafts before you get it all in.
As far as shifters, you can get cable shifters for a couple hundred bucks. Then you can put them anywhere, and won't have to lose your console.
Stazworks is where I am getting my stuff. $600 for the adapter and a new billet shaft. D.D. Machine, Behemoth, N.W. Fab, O.R.D., there are a bunch of people out there making adapters and shafts and shifters.
If you decide to go with an atlas, I personally would just spend the money on a Klune V or N.W. BlackBox. Then you have 4 speeds, whereas with an atlas you have high, and super low. With an underdrive setup or doubler you have high, low, lower, lowest. Just more versatile...