I thought I had found every variation of Canberra's name. Everything from a 'woman's breasts' to a 'berry tree'. I won't add links here but a search of 'naming' in the search function to the right should provide the array of opinion as to the name's origin. This article is titled Yarralumla and that name is discussed also.
This article questions the reliability of recorded place and animal names and their meaning and offers the suggestion that the 'erra' in Canberra means mountain and that anything placed before that is descriptive. eg. Canb-erra = timbered mountain, Jerrabomb-erra = mountain range and that Urri-arra = stoney mountain.
Interestingly Queen Nellie when interviewed said that 'nobody knew'. But as is suggested in the anecdote maybe there was too much 'yabba' (too inquisitive)...
The Federal Capital Pioneer Magazine - Thursday 21 April 1927
National Library of Australia