Noone has done one & posted, so I thought I'd give it a shot. This is the 9v Box w/on-off switch. The pictures in that link don't show the slide switch, but it's there.
The spring came from the C battery box. I had to trim the plate on the spring, it was blocking the latch slot. I used the positive terminal in the 9v box, but not the negative one. The piece of plastic they are connected to is removable, so I filed out a small indention for the wires to run under it. The battery is an 18350. I can get a 9+ hour workday out of one of these. If you modify these battery contacts a little, you could probably squeeze a 14500 in there & still have the built in on/off switch. Or, just slide out the 9v battery contacts. The connector is an 808-D/901. If you use a 901 to 510 adapter, you can vape cartos, 901s, & 510s with this one box. The connector is epoxied to the outside instead of mounting it flush or inside because I have Joye 510s & they get hot. I don't want to melt the box!8-o The switch? I have no idea where I got it. I thought I got it at mad vapes, but couldn't find them.
I normally like the slender boxes(got these on the way), but I like this setup. It works great & I've finally got something that will outlast a carto.
Sorry for the green carto, it was nearby...

I normally like the slender boxes(got these on the way), but I like this setup. It works great & I've finally got something that will outlast a carto.
Sorry for the green carto, it was nearby...