Leeroy,
Just call Vicroads with your list of preferences and see what's available. You can buy the plates outright. You don't need a car or rego to buy them. Different types of plates cost different amounts but my type were about $330 11/2 yrs ago. Up to 6 characters is allowed.
Check out the vicroads web site (
www.vicroads.vic.gov.au)
to check out the difference playes that are available.
Cheers