Dutchy:
If you can get a kit which can be built & certified under FAA regs (eg experimental or whatever) CASA are very likely to approve it here. Mine is coming with FAA paperwork already stamped, and I've had advice on multiple fronts that the CASA certificate won't be a problem at all.
Been through all that. The CH 750 is a 600kg American designed and approved LSA to ASTM standards which is approved as a 51% amateur build kit by the FAA. RAA is limited to 544 kg for kit built LSA. The Ch 750 is now uprated to 650 kg. It has to go the "Experimental" VH register route otherwise its payload is ridiculously limited.
At least if its on the VH register, and has a certified engine, it
might be allowed to operate over built up areas.
However, if I lose my medical the aircraft will have to go on the RAA register, lose 50 kg MTOW (or 100kg if the supposedly long awaited RAA kit built MTOW limit is not upgraded to 600kg).
The first Australian CH750 is being built at the moment (Rotax 912), but then has to go through a "first of type" evaluation by CASA.
What the "first of type" process will probably do, given CASA's reputation, is freeze the only allowable configuration for the Australian built kit aircraft without getting a variation or exemption from CASA, and that both costs money and has an uncertain outcome. For example, I've seen an aircraft grounded over a missing un-vented fuel cap after CASA refused to accept the simple expedient of applying a blanking plate held down with six screws to the full tank was deemed unacceptable.
Yet in America this aircraft is being built with Rotax, Jabiru, Lycoming and Continental engines and is fitted with whatever avionics the builder decides on, let alone fuel systems, autopilots and God knows what changes.
It took me about Six weeks of trying to reconcile the regs with CASA's rules with no success. I eventually was put on to the RAA who gave me about half the answer. The distributor was more enlightening, but the overall level of risk associated with a lack of plain English regulations including what will be allowed and what will not, and the capriciousness of CASA as evidenced by numerous PPrune threads, leads me the decision not to commit $50,000 to a project that may end up "sitting on a pole".
...And yes, I have been told "if you live in outback Queensland no one will bother you", but I don't live in outback Queensland, I live in Melbourne. I've also been told "She'll be right", and that there are various "work arounds" but the regulations don't say that, and no CASA inspector would either.
I want it in black and white in plain English, but of course CASA can't and won't provide that, and neither can anyone else.
To put it another way: You said your kit is "very likely" to be approved.
I have found the hard way in fields outside aviation that "very likely" is not something to base a business decision on. I also sadly note that the "advice" has a nasty habit of not being correct, at which time the advisers melt away like snow in the sun.
I've asked for certainty. I haven't found it, and no one will give it to me. I know I could buy a Foxbat or something else factory built at twice the price of a kit, but that's above my budget so forget it.
Capricious behaviour by public servants is unacceptable. It's killing aviation.