Is beam.NG going to be on other platforms because there is alot of people that play on Mac or Linux and I am one of those people that play on Mac.
Currently we only focus on the Windows platform and we cannot say if or when we will support Mac. However, forum user Zapology has successfully gotten BeamNG.drive running on Mac through Crossover, his tutorial can be found here.
I have also gotten it to work on Linux, but not perfectly. (Tech Demo that is) Installing-DRIVE-under-Linux-via-Wine