That's interesting, I hadn't thought of wanting to purchase a Pak-Lite without an included battery. I've never seen a "naked" Pak-Lite sold, even with the bulk, retail display packs.

The Pak-Lite seems so low-tech that you think you'd find many knock-offs out there, but not sure if I ever have. If I wanted something reliable with that form factor, I personally would stick with the Pak-Lite.

Another 9V option is another oldie, but goodie, the Rigel System Starlite and Skylite. Originally made for astronomers who needed a super-low amount of adjustable light, they are well-built and waterproof. I'm not sure if they have an official website anymore, but it's easy to find retailers online. Unfortunately for you, they come with a new battery, too.

The final option that I'm aware of is one of the very first serious LED flashlights to be sold, the Eternalight line of flashlights. They use a series of small LEDs and have all kinds of different modes. Sturdy, waterproof, and often featured in survival magazines (not sure the web was even around back then) as the ultimate flashlight. Unfortunately, these come with batteries, too.