I am sure (as half of a auto parts supply business and as a Chrysler Jeep driver ) that the reason the parts are so dear for the Chryslers is because they require mostly genuine parts. Most of the parts that you can get for your commodore/falcon/and even kia have after market reproductions ("non-genuine") available (the cheap and cheerful option provided by your mechanic). To the best of my knowledge, there aren't many non-genuine parts available for Chryslers because there's not a huge call for them. If you have a local mechanic, you could ask them about the parts. The Man (the other half of the business and mechanical guru is not here to ask atm.
(As for the embarrassment of my jeep, amongst all the Patrols and Landcruisers of our friends, I am the butt of their jokes for not driving a 'real' 4wd, but I rather like it as it goes like a cut cat!)