To this day I still wonder how I'm like the only person on the planet to nuke 760 joints reliably on 33s. :dunce:
Why do you need two driveshafts to do that?
All the shafts I've ever made are done that way...except I used 1.75" x .25 wall in the middle. Just used the last few inches of OEM tube on both ends.
Wait - nevermind, I get it. 2" x .120 wall is probably not a good choice, especially for something that long. I'm just not a fan of the typical thin-wall tube they use for driveshafts. One dent and you're XXXXed.
Any idea how long it's gotta be? I'd check out this place:
http://www.speedymetals.com
I've used them before with great results. You can buy exactly the length you need of any size tube, and their selection is amazing. Pricing's really not bad too...especially compared to some of the numbers I've seen in this thread.

I'd consider getting a length of either 3/16" or 1/4" wall 1.75" DOM to build the main part of the shaft out of, and just use the stock tube as a sleeve to align the yokes like I've done.
Or say XXXX it, for what you're doing...run a square tube shaft.