I was only cautioning that you should investigate if it'll work safely before you jump in and do it. Your truck had a two piece driveshaft for a reason, so before switching to one piece be sure you can have one made to actually do the job and last.
The Driveline Tech Tip has some great links in it if you're curious why and how driveshafts are made the way they are, also info to help you calculate the max length of a shaft if you know RPM, tube diameter and wall thickness.
A second opinion from a shop that is qualified to build driveshafts would be good too.
Grigg
