I don't know if this has been mentioned before but there is a guy selling a 3D printed cable release adapter for the Lomo Belair cameras. I just received mine and it works like a charm. He also 3D prints a filter adapter for the plastic lenses that come with the camera.
Here's a link to the Etsy site:
Note that there are two versions. One for the all black plastic City Slicker, and one for the leather and metal Jetsetter.
They are different sizes apparently.