Hi Daniel,
If you engage an agent from Sydney, they'll refer probably you to a colleague in Melbourne. It's very important for a buyers agent to have local knowledge.
I've dealt with Lisa Parker 0413 427 075, from Australian Property Buyers on several occasions.
I deal with her because she tends to take a long term view if that's your requirement. Part of her process is to ensure the purchase made now will support your ongoing goals, such as leveraging to buy several properties.