I have just discovered that Klais restored the organ of Maria Himmelfahrt in Niederschönenfeld. This has two keyboards on opposite sides of the case playing at different pitches...
The organ is on a west gallery and which was originally divided and had a parish side and a nuns side. The keyboard on the parish side was used for congregational singing and was at a lower pitch. Whilst the keyboard round the back of the case was used for accompanying the nuns who sang form the gallery at higher pitch. To accommodate the challenges of playing different keys in non-equal temperament there were separate pipes for B flat and E flat to each manual, but the other pipes were shared.
Following the mention on the Organ Design thread of the organ in the Disney Hall, Los Angeles, I found this remarkable video from 2012 of a 16-year-old organist. I hoper’s fulfilling this early promise. The organ sounds great too.
Although I am unlikely to own a pipe organ (unless I acquire a house with one - I ended up not learning for as long as I would like due to the local church being kept locked after the verger left) I would prefer to have a box organ. The temptation would be there to have some pedals with it that could be detatched for transport if desired: I have come across something like that before.
This example is taken from the website of Škrabl - https://www.skrabl.co.uk/small-organs.asp - and is advertised with the specification of Bourdon 8, Flute 4 (both wood) and Principal 2 (Metal) with a 56 note compass: the pedals, if I had them, would play from the Bourdon 8.