Current technologies e.g. Spot and likely future technologies allow tracks to be viewed on a web page.
One option would be to allow you to register a web URL for your aircraft for whatever tracking device you had. AMSA could protect it so they could only access it after a SAR phase had formally been declared.
Allowing the URL to be submitted with a SARTIME would also be a good idea. (Actually, I have wondered whether you could put a URL in the Remarks field.)
This would have minimal cost and allow the user to choose the technology they use. A spot tracker costs a couple of hundred dollars, plus a couple of hundred US per year for a plan that tracks automatically when the device is moving.