I finally got my hands on a Mobilinkd TNC 4 and needed a way to keep it together with my UV-5R that wasn't a rubber band wrapped around the whole thing. With access to a 3D printer I gave a try at designing something that would do the job.
I got the TNC 4 to make portable packet operations easier, but quickly found that trying to hold the little TNC with the radio was a bit annoying and using a rubber band didn't work well with the belt clip attached. I haven't done much in the way of 3D design work, but I went over the Tinkercad and gave it a shot.
It was a simple enough design, but it took me a couple tries to get the tolerances to where the TNC would fit snug while not getting stuck or falling out. The case has a pathway through it so that the radio's belt clip can snap through it and hold it to the radio. I had also heard that previous versions of the TNC were susceptible to having the button pressed in error, so with this case you can simply insert the TNC facing the radio and cover the button completely.
To download the file and print it yourself, head over to Thingiverse.