Thanks for all feedbacks!
I have further questions/comments here:
1) Could I use BIAB with an immersion heating system? If stainless steel, shouldn't it be fine?
2) How does coil HERMS work => could I use one of these (
http://www.theelectricbrewery.com/custom-herms-coil) with my SS brew kettle without having to make a hole in the kettle?
3) To answer to morticaixavier, for a double portable induction set up, one guy is using that technique with success apparently, see
https://www.youtube.com/watch?v=tMHNPCNYAwwHard to decide when my budget is limited to around 200$/300$...
Cheers