The Z axis extension fits the enclosure again when the bottom sheet is omitted and the enclosure lifted up by some 55mm.
I had U-shaped aluminum profiles with 3mm walls lying around that exactly fit the profile groove of the enclosure frame, as well as some pieces of plastic 3mm thick … voila, a near perfect enclosure extension.
Still some work to do on the details, though. But I like that the enclosure is back … no ABS smell.
Btw., the z axis extension soon came in handy for me