Jeffy, you had the bottom two shafts reversed. Middle is a stock TJ mainshaft cut for a H&T, and the bottom is a YJ shaft. The TJ shaft has the extra journals on the end for the seal, and a different hub surface that includes a groove since no roller bearings are used inside the TJ hub. My YJ mainshaft was a rare breed, being a '95 it had similarities to both the TJ and YJ shafts.
That being said, I run a H&T and haven't had any issues. I used a shortened front CV shaft from an XJ/TJ and simply replaced the front half of the CV with a flange mount to mate to the H&T. Not as short as a standard HD SYE but it works. I saved some $$ and used the TJ H&T with a TJ mainshaft and tailshaft housing. A lot cheaper.
I've only replaced one broken stock mainshaft in a 231, and the guy was jumping his jeep. It broken in the same place as in oldjeep's pic. I think his wheels were spinning in the air, and when the front end landed they slowed down suddenly. The remaining inertia in the rear tires caused the mainshaft to snap like a twig.
I think I'm gonna go with the super short SYE from PORC, it's only around $230 and it's a ton of extra driveshaft length. The speedo will be close enough for the ECM to function correctly, that's all I need.