I've got a great idea for a feature: Linux deployement support!
Come on, I'm sick of people leaving the penguin guy behind.. Or worse yet, only developing for X86 Linux.
I wouldn't know, because I haven't seen the Unity code, but I know that:
b) Mono is made almost exclusively FOR Linux, which is what Unity is coded in.
c) The AgeaX PhysX engine is being ported to Linux (by AgeaX).
d) OpenGL is available for Linux, and most Mac ATi Cards do support some form of acceleration in Linux (I've tested: Rage 128, Radeon 7500, Radeon 9200).
Please don't say there isn't a big enough market, because although it isn't a very big market, it means that there are less people developing for it. Maybe if more people developed for it, there would be a bigger market. Also, if there aren't many people developing for it (Especially Linux PPC) you will have almost the entire 3D game market (or rather, your customers will). What other 3D games are there for Linux? Quake? Doom? Unreal? Sure, those are all great, but watching pieces of flesh being ripped apart and thrown all over the screen doesn't appeal to the whole market. I mean, wouldn't it be great if a game like the original Nanosaur was available on Linux? Yeah, of course it would!