Well, I found out something interesting when I went out to work on this problem today. I put the Tcase into 4L and the light came on etc... I was able to move the vehicle and all that, but then I decided to gently nudge the shifter (I have no idea why). It popped out of 4L into neutral. I then pulled the lever back up and re-engaged 4L and shut off the engine. I got down underneath and shot the linkage with PB Blaster (a must here in NE Ohio!) and loosened the lock bolt. The linkage slid forward a good half-inch before positively stopping, at which point I re-tightened the bolt.
Now, when I engage 4L, there's a positive "clunk" from the T-case that I never had in this Jeep before. It goes into 4L and stays there until I purposely shift out. Apparently, the linkage had never been adjusted right from the factory but was close enough that it wouldn't pop out of 4L by itself and I've just been lucky enough never to have nudged the shifter while driving. It's only since the T-case drop made it a little harder to move that I noticed it at all.
Patriot, I did manage to dig up the relocation bracket from the evil garage-demons, but Since the linkage is working smoothly without it now, I don't think I'll be installing it. The angle is not too severe and I think It'll be fine. Once I get my SYE installed, it's all going right back up, so it wouldn't be permanent anyway. Thanks for the advice though.
Thanks to all who answered!
2004 Patriot Blue Wrangler X, 33"x10.5" BFG Mud Terrains, 4WDH 2" lift with 3/4 inch spacers, 1" BL, 1" Brown Dog MML, Yukon 4.56 gears, Yukon Super 35, ARBs front and rear, Warn 9.5ti winch, GPS, MP3, Some hooks and lotsa skids.