Even for a stock outer that would work. Flip the bracket over. Rod ends have some advantages in this application. Ready avlibility, easy R&R, heck don't even need to remove the arm to replace the bearing, all win win in my book.
Inside becomes a bit of an issue, but plenty of bearings to do just that at the local farm supply store.
In reality, I would Move the bearing into the arm on the inner side and let it go.
"Very cool! Is the new rod running through the trailing arm fixed in someway to the arm itself?" the bearing would turn ssepart of the arm shaft, just like it does not.
These are the exact same.
So now what are we missing. Roller bearings in the arm make pvferct sense as it keeps the arm and the bearing and shaft all in alignment. The issue is the angle at the end. Just use two pieces maybe 4 to solve the problem. Since you want the nut o the shaft to be seated flat to keep your settings. a semi circle washer with corresponding cup, on both sides solves your issue, and keeps everything working correctly while providing the movement you desire from the arm. You may need some thrust bearings on the outside. Muellers kit had them, and then everything works perfectly.
Look something like this. Concept, not final engineered solution.
Click to view attachmentBTW, that will cost you roughly $25K in consulting if you use the design or idea.