I got tired of the crappy connections I was getting from aliexpress 18650 battery holders so I bought some terminals on Taobao and made my own case. First attempt is usable, could be smaller though. The terminals are held in place with hot glue, nothing fancy.
Openscad source is here. 18650.zip (500 Bytes)
Version 2.0, thinner walls, hidden terminals and the option for two cells.
18650.zip (13.8 KB)
Cool and Awesome!