Unless SteamOS and Steam Boxes becomes a thing releasing native games on Linux doesn't really make sense unfortunately, cost of customer support alone would be prohibitive, and the negative backslash from the Linux community if Linux distro X on hardware Y is not supported would do the rest to drive devs away. The most realistic distribution platform for games on Linux (unless SteamOS takes off) would actually be HTML5 games using WebGL for 3D rendering. In this case the browser vendors do all the hard work to provide a unified platform wrapper (not that I ever got WebGL support working on Linux in a VM though).
I don't know if you can make a serious game with js though. ASM.js might help, the 3D demo from the unreal engine showed a decent framerate, but I don't know if it can go from the neat demo to something that can be sold.
