Awesome, I love the success stories!!
So on the 1xAA box, the top positive terminal near the battery conn fits into two grooved little channel things.. Take out the connector, carve out the channel things and then epoxy the connector to the top of the box. You may have to take a little bit off the spring on the negative terminal, but that's optional depending on how tight of a fit you want with the battery. By moving the top terminal you can gain the mm you need to get a 14500 protected battery in there.
I'm doing another tutorial with the 1xAA box soon.. (as soon as the wife stops thinking I'm having an affair with my new drill press

)
Thanks for the kind words..
Hoog