This is a remix of 2 great joycon holders:
http://www.thingiverse.com/thing:2172789 I used the light holes from this model and used http://www.thingiverse.com/thing:2269630 because it's the only one that actually locks the joycons.
I also added the Nintendo Switch logo and set it up ready to be printed with no supports and the rails are pretty sturdy more so than any other holder I've printed.
Joycons might be a bit tight on the first few inserts so use a little force.
Try it out and let me know your thoughts, thanks to both other creators for sharing their files without them this would not be possible.