Everyone seems to have their favorite material, but Aluminum actually is ideal once a flashlight gets larger than a AAA/10440 or a 10180 light (which can use any material because they are small, and material mass and weight is an advantage in a light that small). Aluminum is ideal at the size of CR123A or even AA, due to its lightness and especially its heat properties, both superior to stainless, and it is strong enough as it is without modification for U.S. military and law enforcement. Also, Al is more affordable than stainless, both in the material itself, and the tooling of it will require less replacement and refit for the wear of milling it causes. This cannot be overlooked. Tough Titanium is chosen at times, for its strength and low weight, even though its heat properties are worse than stainless, and it is very expensive. I think maybe it is mostly its strength and its bling that it is seen in premium and collectable lights like
McGizmo (E-series thead compatible!) and
Sinner.
You should consider that things are what they are, and instead of trying to force a duck to be a goose, take a look at what Fivemega has for sale:
bimetal, and another in all
stainless.
But the ones who know keep coming back to Executive Elite, and LF corrects the pain of the rigidity of Surefire's strict business plan, never offering the parts we want for sale separately. You just have to see how great this is that these LF bodies are now painlessly readily available. So by all means, if you want to bore for 18mm cells, there are services, knock yourself out, because if you do have problems with weak threads, now you can replace the body effortlessly without the anxiety of not knowing if you can find a used one on eBay to modify. But I see wisdom in LF's decision to keep the design the same, as it is a direct replacement, and those who have put it through the tough duty know it works. Change a product that works even a little to appease the fringe and you are taking a gamble.
I'm not sure I have seen any Surefire flashlights in HAIII Natural that have a bezel that matches the head, or matching body or tail. Sometimes the tail matches the head, bezel matches the body, a little, but never seen one as you describe that meets your high standards. Certainly I have never seen any that match another identical light either. So please don't beat yourself up, and don't go bankrupt trying to achieve the impossible! HAIII Natural hardware is expected to mismatch.
Also, congratulations on
your matching! Here's to a long and happy marriage!