I suspect the installed-weight of any of the Rotax 912-family engines in a Jabiru airframe requires significant compromises in either fuel or crew-weights.
I've heard of Rotax installations in Jabiru airframes. I have actually met someone who claims to have flown one. I have seen a photograph of a J160 purporting to have Rotax 912 installed in it...but I have never actually seen one of these aeroplanes, nor have I seen any review of the performance (or possible lack of it), or the pros and cons of the installation, etc etc etc. Additionally, it is only an option (if it is viable) for home-builders.
Putting any Rotax engine into a Jabiru airframe isn't a simple task. Attractive? Yes. Simple? No.