I have been getting a good steady supply of B&W reversal from John Schwind on the internet. Although the film is 16mm wide, it needs to have twice as many perforations as standard 16mm film.
The main problem for me with processing it myself (which I would not mind doing) is getting it split afterward. It has to be a precision split, otherwise the film won't make it through a projector.
For 7 years I have used Prep Film services for processing and splitting.
The Bolex 8mm splicer is another precision device. It actually tapers the two film ends and preserves the emulsion on one side, so the splice area is not much thicker than the rest of the film and no image is lost. Depending on how well you do it, there will still be a fine line across one frame.