My Bike-E recumbent doesn't have a conventional seat post to mount a rear tail light onto and I don't want to drill the extruded aluminum frame. I made an adapter that slides into the frame that any standard seat-post accessory can mount onto. This will allow me to add my state-mandated light or reflector.
Print (1 extra shell, 10-25% infill)
Slide into Bike-E frame (it should be a tight fit)
Mount tail light.
If you are interested in one for your Bike-E contact me and I'll print one and mail it to you for a nominal fee (to cover plastic and postage). I know there aren't a ton of Bike-E owners still but I still love mine.