Unfortunately Squawk I have to disagree with you for simple financial reasons. If CASA were to mandate something like this, then some bastard in Macquarie Bank will use it as a licence to print money at the expense of the aviation community.
Spot, etc. are subscription services the tracker thingie just beams its signal to a satellite where the owners of the system have a transponder account and the message is downlinked to Spot Inc. you get access to the data via their website.
By the time CASA came up with a specification for a system it would be:
(a) Completely at variance with todays commercially available solutions - designed for "Australian Conditions" so that someone in CASA can write their masters about its unique design. Needless to say, unsaleable too the rest of the world.
(b) Massively over engineered even by European standards. ETSO'd etc.
(c Supported by draconian regulation with respect to fitment, modifications and of course onerous operational and maintenance conditions, perhaps forbidding flight at all if the system is inoperative and requiring maintenance by a certified facility conveniently located in Alice Springs.
(d) Managed by a subscriber organisation whose idea is to suck the life out of a captive base of customers.
In other words, a complete cluster****.