Check out the Romisen RC-H3 at DealExtreme. I'd provide a link, but the site is down for maintenance. It's surprisingly bright on a single AA alkaline. It's got a single mode forward clicky instead of a reverse one and won't tailstand. Barrel is narrow so only alkalines or narrow Nimh like my 2300 mah Tenergy fit. Duracell 2650's or Kodak Hybrid cells are too fat. It's only about 15-20% brighter on Nimh. It's bright enough on alkaline that no one's going to complain. Best of all, even though it is branded "Cree" on one flat, "Romisen RC-H3" on another, it's got a 3rd bare flat that could be engraved with your business name. My wife loves it, the switch is easier for her to push than the one on the MTE single mode Rebel I'd given her so I gave her that one instead. I've got a half-dozen of them coming for Christmas gifts. It's exactly the same size as the Ultrafire C3, small.
It's only about half as bright as an Ultrafire C3, but it's 4 or 5 bucks cheaper and the C3 doesn't have any free space to engrave unless you do it on the barrel. Probably will last a lot longer on an alkaline AA, too.
Edit: I have an apology to the RC-H3 to make. I'd forgotten that I had a 14500 in the C3, not a Nimh. With both on Nimh, the C3 is still brighter, by about 30-40%, but not 100%.