I don't usually like the squat little portable cases you see around that are made for portability, but this one does it right. iBuyPower has used NZXT's Rogue case and filled it with things you probably wouldn't expect in a LAN-going box. Liquid cooling, room for 4-way SLI and a huge amount of RAM, and even two optical drives if you want.
I guess the Rogue case isn't exactly micro, but it is of a more portable form factor than, say, the Whisper. With the carrying strap included with this system, it'd be pretty easy to hump over to the car and toss in the passenger seat.
It's pretty configurable, so specs wouldn't really serve a purpose here. Go check out the configurator and see what you can get. It starts at $1000.