1841-1851 is tricky because it falls between the census of NSW in 1828 which caught almost everyone, and the date when most passengers were named, rather than just counted, on many shipping lists.

These may be worth a check:

http://proarchives.imagineering.com.au/index_search.asp?searchid=24

http://proarchives.imagineering.com.au/index_search.asp?searchid=23

http://www.records.nsw.gov.au/archives/search_1656.asp

http://www.records.nsw.gov.au/archives/indexes_online_3357.asp

http://www.bdm.nsw.gov.au/familyHistory/search.htm

http://www.coraweb.com.au/local.htm

Perhaps "Barbara Fargher, Research Assistant...." could help with Adelaide families!
http://www.artgallery.sa.gov.au/2005/EX05%20VisionsOFAdelaide.htm

Sue