The design has come a long way, frogprince. We have a Canadian model. Looked at a Swedish one but decided on the Canadian one. It works the same way as those tumbler compost drums but you can't see the workings from the outside. It has a handle that turns the drum. In the drum is a mix of peat and wood-shavings and you add enzymes with a sprayer. When the drum is 60% full you turn it backwards and everything is dumped into the space below the drum. From there it dries out and you empty it via a small tray about once every 3 months. The unit has a pipe up through the roof that draws off gas and water vapour. It has a fan for use in still weather and in very cold areas you also need a small heater.
From the outside it looks quite solid and you'd never guess what was going on inside.
There are links down here. Isn't that helpful of them? Ours is one of the Sun-Mar models.
Cheers, Joy