The hose of my good old wet-dry Bosch vacuum cleaner broke and even taping it didn't seem to last long. Replacement parts were surprisingly expensive so I decided to use an old spare hose of an standard Siemens vaccum cleaner.
All I needed was an adapter for the different diameter (actually the original hose had different diameters on both ends, i.e. all nozzle parts for the thin end still fit well on the "wrong" hose).
Both ends are slightly conic (the vacuum end on the outside, the hose end on the inside) to allow some tolerance and easy connection.