Access cab rear speaker placement

I’ve been reading about the value of the rear door speakers and how much they contribute to the overall sound quality within the cabin. I know with the stock headunit, the rears are already not in balance with the fronts.

With an access cab, the rear speakers feel, and seem even more worthless than they do with the double cab, so I was wondering if anyone has thought about, or has placed the rear speakers on the back wall of the cab?

My thought is I’ll build a storage cabinet and on the top, just underneath the windows, I’ll mount the rear speakers facing the headrest/ceiling to provide for a richer, fuller sound in the cabin with more direct sound.

By the way, my plans are to add a line output converter, an amp and speakers all around, including a sub in a sealed box.