As you may already know, Kiali included some multi-cluster features on 1.9.0 version.
The multi-cluster effort has a broad impact across Kiali and, eventually, everybody involved in Kiali development will need to do/test/review new multi-cluster changes.
Since you are in kiali-dev list, you most likely will need this kind of setup :)
So, I wrote some scripts to automate an Istio multi-cluster setup. I uploaded them in a gist. This is the link to the gist (to the main script) with some doc at the beginning:
It's not extensively tested, but I hope it works most of the time.
If requirements/assumptions are not suitable for your case, I hope it works well as a baseline for your environment.
So, if you are interested, please try. Feedback is appreciated.