But is strength really a limitation when it comes to an aluminum-barreled flashlight?

How many aluminum flashlight barrels have you bent or broken in the normal course of use? (If you used your 6D Mag to thwart a burglar, I'd say it can be honorably retired.)

When was the last time you had to re-sharpen your aluminum flashlight barrel because it got dull?

There *are* many uses for titanium. Flashlight barrels aren't one of them. I can't think of a single reason why I'd prefer titanium over aluminum for a flashlight, even all else being equal (and all else is not equal, most notably price). But they'd still sell like hotcakes for the reason I gave, so if there's some enterpreneur out there, I can tell you there's a dormant but lucrative market for titanium barreled flashlights.