Awesome idea! I have been toying with using a LiteStep theme with my CarPC. Something designed to look like MediaEngine (not a port but similiar in layout) incorporating the basic functionality of a true "Media - Engine" into Windows would rock! I like the look and feel of MediaEngine just not the extra overhead of Windows. I've not written and Themes for liteStep but use it on my laptops and my home machines.
Keep me posted!