I have only ever seen 2. I don't think either were built by lister though. I have a Stamford gen head that I brought over from the UK that was on a cast lister base with a VA. I don't know that it had an som type box or load sensing circuit but was set up for pushbutton start and shut down and the VA had the som fuel control mechanism.
The other was a guy here years ago that was trying to sell a bunch of stuff he had brought to the US from the UK. I remember him posting a video of a VA setup on a base with an SOM head. I believe it too was built by a generator company rather than lister.