Hello Robyn,
Elizabeth was lucky to survive that awful voyage on the fever ship 'Ticonderoga'!
One doesn't know whether "Midlothian" is meant to be her birthplace, or the place where she was living before she went to Liverpool to board the 'Ticonderoga'. If the former, I wonder whether 'Rossland' might be a misspelling of the village of Roslin (Rosslin, Rosslyn) in Midlothian (a few miles S of Edinburgh)?
The Fife record which Jonathan found is tempting - but, before statutory registration, so many children were not recorded (or records didn't survive, or haven't been indexed) that I guess you really need some further proof if you are to tie her to the Balmerino Elizabeth with confidence.
Perhaps you'll need to wait until there are country-wide indexes for the 1841 and 1851 censuses of Scotland. ScotlandsPeople has been promising these for quite some time and we have all been waiting on tenterhooks - but the date they were supposed to be available has been steadily disappearing into the distant future and now no estimated date for availability of these indexes is given on the SP site.
I see that the 'Ticonderoga' site at
http://ruzoz.customer.netspace.net.au/Ticonderoga.htmmentions the name of someone researching, or descended from, Elizabeth - I expect you've been in touch with her.
Regards,
Judy