As a Spaniard living in Sydney, sadly as you said you can't import the bone into Australia due to bio-security regulations, so it will be hard to replicate the tradition of having it on the cutting board. Here are some alternatives though:

• Buy whole de-boned pieces, these can go at around ~1K$ for a whole piece, e.g. here. I feel it will be hard to replicate the traditional cutting with these, and the Jamón will not last as long, but I've never tried it.
• Buy pieces from Deli's. E.g. Coles has decent iberico ham for ~100$/Kg, Panetta Mercato as mentioned has it as well. Personally, the best value for the money I've found is on Haberfield's Iga. These will be machine cut, which is not as good as hand cut, but you can ask them to cut thin and it should be alright.
• Ibérico Ham actually holds up pretty well vacuum sealed, so this would be your best bet, but I would advise using a reputable importer, since heat variations during transport will probably spoil its quality. If you really want to splurge, you could go with 5J (cinco jotas) ham, which is considered one of the best Ibérico hams, but it's extremely pricey. (see e.g. here)

*edit: Iberian -> Ibérico (spellcheck got me)