Cost is not an issue, a friend of mine has a bright pink suitcase (bordering on fuschia) that they're willing to sell over for a few bucks.
I'm more wondering about the check-out/check-in issue though. I think I will ask to retrieve my baggage at every transfer. At least that way, if I get to LHR and it's not there, I know for certain it's in Sydney (does this make any sense...?)