Flooi wrote:Rotax powered Jabiru?? Why has someone not taken the plunge??

They certainly have... in Australia at least.
Here's one for example:
https://aviationclassifieds.com.au/listing/5427
I'm aware of two 914 powered J230's, there could be more.
There's 1 x J430 with a Lycoming 0233.
There's a couple of J230's with an 0233 but they may be in the final stages of conversion, I'm yet to see them yet.
There's at least 5 J160/J170's with a 912s fitted and possibly more I don't know of.
All reports with the 100hp give an excellent climb rate, but not really an improved cruise speed, or certainly not a significant increase.
The J430 with 914.... excellent climb, like 1,500+ but not am amazing increase in cruise compared to the 3300 with timber prop, which is somewhat surprising.