I e-mailed Chris twice about the early 3 threaded N to AAA tube but no replies. I know this is the "holidays" so I'm sure he's taking a well deserved break. I'd probably never use it for my proto N cell but it would be a nice accessory to have, just in case.
Even though they have some drawbacks, (runtime mainly but that could be nill with a 2-stage), I think CR2 and N celled lights are the only way to go for a true miniature light. I even predict they will take over 123 based lights in the future as the most popular small lights. As Larry always says, the complete lights can fit into a 123 based light's body!