[Arran]

I don't know how rare this particular model is, since it has a six tube chassis the chassis itself is probably not that rare since it would have been used in a console model, and probably a horizontal shaped mantle set too. Some radio manufacturers in Canada offered table sets in this sort of vertical layout, Rogers being one of them, but I have seen some RCA sets with a similar layout, probably others. It may have been due to the British influence, or they were simply trying to create an updated version of a tombstone design but with the dial at the top rather then the speaker. Honestly I've seen more unusual designs in U.S built sets, such as AC/DC sets with pushbuttons and a Magic Eye, various chairside and coffee table cabinets, bar radios, steel cabinets, etc. However there were some odd American RCA models that look a lot like this Rogers, if you look through their service manuals you can see a few.
  As for the 6X6 tube, I wouldn't worry about that right now, it isn't necessary to get the radio to work, fortunately the rest of the tubes have industry standard equivalents, metal or GT style tubes work fine as substitutes. For example a 41M is a 6K6, a 75M is a 6Q7, etc., the rectifier is probably an #80, all very common.
Regards
Arran