SqueezeMe:"Goran says: "The bellows *can* be massproduced and treated as comsumables but that hardly helps much..."
Excuse me. Who? Where? How? Pray tell".

RE:For fun I tried once a piece of the kind of building ventilation tubes 5" diam and with a 'sceleton' from a spiral metal thread. (used for citchen fan exhaustion for instance). Cost 1-2£. Not very attractive but it works.I would not recommend it... Consumabble bellows otherwise could be possible to produce 4-12 sided in one piece with a similar'sceleton'. All the same I don't believe in the idea, it still is the rest of the 'box' that is too expensive.