Well, it took a week of evenings but I got my drivetrain assembled. Toyota W56 5 speed tranny, stock toyota reduction box with 2.28:1 gears, a Trail Gear doubler kit with 23 spline coupler, a 2nd toyota reduction box with 23 spline 4.7:1 gears, and an inchworm gear lefty case with Trail Gear twin stick shifters.
The combo worked out better than I could have hoped for; looks like both of my driveshafts will be in the 30" range...plenty long enough. The angles on them will be excellent...only a few degrees at ride height. I managed to get the bottom of the tcase almost 4" above the bottom of the framerails, so ground clearance won't be any issue. The only cutout in the cab will be hidden under the driver's seat (I'll box it in after I'm finished building the crossmember). And yes, I plan on using something stronger than a hemlock 2x4.