Many thanks to CBX!
He promptly delivered it after reviving payment. We had exchanged emails including all of my serial numbers prior to payment.
I purchased 10 DS-2CD2232-I5 (another 3 on the way) cameras from Aliexpress completely oblivious to the fact that they were Chinese and would have any issues. After applying the region code change, they operate just like English cameras.
They came with 5.10 firmware which the distributor had downgraded from 5.1.6 (it said 5.1.6 on the label on the bottom of the camera) specifically to return the camera back to English since 5.1.6 doesn't support English on Chinese cameras. In any case I was afraid to upgrade while looking into hacking the firmware when I discovered this solution.
After applying the region code fix, I was able to upgrade to 5.1.6 as if it were English.
It's not free unfortunately, but I believe CBX deserves compensation for his work and this keeps it from falling into the wrong hands. Also I still save a ton of money buying 10 cameras from China and hacking them this way. That being said I'm reluctant to buy from Aliexpress from now on.
One thing I'll say is that I'm glad he's keying these to camera serial numbers and not giving this away freely. I don't want this tool to fall into the hands of the China suppliers. If it does I'm absolutely convinced they will start using it to hack cameras and sell them as English (or as they explained to me "international market version",) then Hikvision will start finding new and creative ways to thwart it in future firmwares causing us new headaches. Currently this solution works and as long as it remains in control of the customers, it may work indefinitely (hopefully.)
I had 3 more cameras coming from another distributor on Aliexpress. They arrived with 5.1.6 firmware and the UI was all Chinese. I placed another order with CBX and he added the 3 serial numbers to my existing 10. After applying the fix, rebooting, the cameras came up as English.
My experience is that he's friendly, professional, and stands behind his work.
I really recommend this fix over hacking firmware. You'll reduce your headaches in the future.