I have seen quite a few over the years, in the possession of flyers of course. So they are certainly available to aviators for their own RTW activity and I have seen them in various scales, depending on what they are intended for, from large scale plans of airports to world atlases and everything in between - as a thought, those fancy, bulging flight bags that pilots carry around will be packed out with similar ones!
I don't know if it is easy to obtain them - I have never considered it because the scales that I have seen in greatest use are not all that useful IMO. I do have one or two as "souvenirs" of flights I have been on - always liked looking at maps as it happens.
As a minor point, air planning charts are covered in symbols and markings that are of no relevance when on the ground (flight paths etc etc), so I don't rate them for land navigation. You should be able to get 1:1 000 000 land maps (& other scales for that matter) from whoever does the national surveys in Oz and elsewhere (Ordnance Survey here in the UK).