Considering going from Brisbane to Rome.

No, problem! That sounds a bit odd...such a big price jump! You may want to check your travel agent or some online travel sites such as webjet or expedia - sometimes they have very good sales and I have landed on a couple before. Once, Etihad was quoting me around $9000 online for a business class flight online, and I went to get a quote from my TA, and they quoted me just under $7000. If you are not in a rush to book then wait for specials as they happen often, if not, I hope you have a great trip, and especially a great flight on Cathay!