Its been asked for many times before but I will add my voice once more
I would pay again if there existed a B4X IDE for OS X. Its only fair to Erel, if he works so hard to produce this, that he is paid for his extra work.
Its not uncommon to pay for separate licenses for Windows or Mac versions of the same program.
I am using WinXP 64 in a VM on my Mac Mini and MacBook Pro. A Mac IDE would remove a lot of unnecessary processes (a whole OS for a start!) and be well worth paying for.