Roger,
Rollei did, in fact, make tele and wide angle attachments called Mutars (0.7x and 1.5x). They were make in bayonet 2 mounts but rings were available for types 1 & 3). These are described in the addendum to Alec Pearlman's 1966 edition of the Rollei Manual. Prior to the Mutars, Rollei produced the Tele-Magnar attachment during 1939/40, but this bizarre creation was soon withdrawn. It gave a focal length of 30cm! Unlike the Mutars that had matched taking and viewing lenses, the Tele-Magnar contraption was bayoneted onto the viewing lens and then transferred to the taking lens.
Zeiss also made the Duarnar 2x attachment in 1953.
Rollei certainly produced some strange accessories. Can you imagine some of these getting past the bean counters now?!
Ray