I'd agree wholeheartedly with tggzzz, it sounds like you really need to get a compliance testing house involved, not just to do the work, but to specify *exactly* what the testing will be bearing in mind the rather casual "ten times consumer output".
RF is a funny thing, and I don't mean funny haha either. Getting controlled, repeatable measurements is very, very hard. I don't know what category of aircraft you're talking about, but at one extreme you could be talking about needing a very large anechoic chamber.
One thing that concerns me, are there not already standards in Australia for certification? In Europe we have EASA and ETSI approval for each piece of avionics equipment. Admittedly these are unit tests, not a system test made once the devices are fitted. However typically the immunity levels provided by the type approvals process mitigates this to a large degree.
At the other extreme, you could simply use a carrier wave from a signal generator with an HPA and a dipole at various defined frequencies in various locations of the aircraft and see if that affects any of the avionics. The problem with this is that it also means you're going to need to have a means of testing your avionics at the same time, for example your transponder, TCAS, weather radar, GPWS, FMC, ACARS, ILS, GPS, VOR and DME equipment. Furthermore, typically the equipment might not just fail completely, more likely it will become less sensitive due to front end (or other) overload. In addition, it might be the faults occur not with a carrier itself, but it might be the modulation on the carrier. Also remember that a lot of interference is caused by complex mixing products, so testing at one frequency in a band could well be not enough.
There are lots of dimensions to what you've proposed, and it's difficult to see how it could be achieved without creating a set of reasonable technical criteria first.