Here is one I did a few years back .
I have a Minolta D7 and wanted to use it for imaging but found that the large lens on the D7 vigneted badly in eyepiece afocal imaging . Scopetronix had only the maxiview at the time which was a 11/4" so i knew that was not going to work as the lenses were to small .
I had this cheap Skywatcher 42mm 2" kelner eyepiece and it had a nice big eyelens on it , just about the same size as the Minolta lens .
I machined down the housing so the ep lens and the Minolta lens almost touched made up a bracket to hold the camera and hay presto .
Posted a few pics on a couple of US forums got some interest and guess what a few months later Scopetronixs came out with almost exactly the same set up in 2" and they even used the same eyepiece >>>>>>talk about coincidences?????? I notice a big patent pending logo on there web page .
Conspiracy theories any one ?
:p