I don't know anything about the rebates from the private insurance. But you will get medicare rebates. It depends on how you are paying for it though. I know there is a way that you pay less, and WFC claims the medicare rebate. But each cycle costs about $1100 or so.
We have always paid the money up front (hefty $4k) and then claimed the rest back when we get the itemised receipt. It's hard having the $4k in the first instance, but our first cycle we got everything back except about $1500 and then on the subsequent cycles it only cost us $290 odd (more if you have lucrin or hgh) as we had reached the medicare threshold (which is calendar year, not tax year). Don't forget to register for family threshold with medicare for both you and DH if you hadn't already)
I don't have full private health insurance for pregnancy, as all of the ob costs before the birth aren't covered and then you can still be out of pocket quite a bit for the birth. I've researched it and it's about $4k out of pocket for a private birth, on top of the extra $$ for the higher insurance cover. I can't really justify it for myself. I figure if I need to have extra care I'll just pay it out of pocket, the money is better sitting on my mortgage till I need it than in the insurance companies hand! My personal opinion though, not knocking you if you have it and can afford it!