Hey Nicole!
As far as I can tell, everybody does indeed need to get a medical done, especially for spouse/defacto visas as it is a pathway to permanent migration.
Here is what you can do though--submitt your application and wait to get a CO. Once you have one, they might send you an e-mail saying that they will contact you again on date X and that in the mean time you can do your medicals and any outstanding character checks (police certificates). I think that one of the reasons why they tell you to wait is because some people do not require X-rays......
O.K ive had a read again of the health requirements (i remembered when i was doing it that i figured it out and I just found out how i did it again).
If you look here:
http://www.immi.gov.au/allforms/pdf/1071i.pdf
It talks about permanent migration and the health requirements and so on. The thing is, that while a defacto visa is temporary for 2 years, you are actually applying for your permanent residency at the same time. So, if you look at the temporary visa health requirements here:
http://www.immi.gov.au/allforms/pdf/1163i.pdf
On the second page, in the far right column it says: "All permanent and
provisional visa applicants are required to complete:
• a medical
examination
• a chest x-ray^
• an HIV test if 15
years or over."
Thats how i figured out that yep, I needed to do the health checks. Check on the immi website to find a panel doctor near you. If you have a few options, i would shop around a bit as i found out that prices ranged from just over $100 to over $400 near me. Plus it might take a few weeks for you to get in to see a doctor, and since you have to have HIV testing, it can take a week or two to get the results of that...
So, post your application, and you can always book your medical so that it is completed while you are waiting to hear back from your CO. Waiting to get a CO does have an advantage as--you can ask him/her questions, and, you will be given a file # so that when you do send him/her other stuff, you can make sure it will get there quickley.
Sorry i went on a bit there, its just that I have been telling people that everyone does have to have a medical and I wanted to make sure i was right.
Good luck and let us know how you go and what you decide!