Had a few questions about this and didn't realise how little info I've actually put here.
It survived summer no problems, although I don't leave my car in the sun...
Final specs:
Software:Windows 7 (sripped down to the basics, custom boot logos etc)
Centrafuse Auto 4 with maps as a front end, music player, navigation etc
SOON: Sygic Fleet 10
Hardware:Motherboard: AsRock H77M-ITX
CPU: Intel Core i3-2100
RAM Patriot G2 Series DDR3 1600MHz 4GB
SSD: OCZ Agility 3 60GB SATA 3
Case: Mounted to a cut out motherboard tray, velcroed to the airbag module
PSU: M2-ATX 160W
GPS: BU-353-S4 Sirf Star IV USB
Bluetooth: Cheap USB adapter
OBD: Tactrix OpenPort 2.0
Cables: HDMI, lots of USB extension cables, various 3.5mm cables etc...
Digital Radio: MonkeyBoard DAB+ Pro Board
Webcam: Logitech C615
All running well, I have it all set up so I can log my car or take a learning view snapshot with a few clicks and have the screenshot transferred straight to my desktop computer. I've also been using it to load up tune revisions.
Been using the full HD webcam to record video at track days, working brilliantly apart from the audio quality sucks and the little i3 takes a few minutes to process a 1GB video

Added up what it's ended up costing me, not the cheapest option but I'm happy with it and it's definitely been worth it. Having said that there's room to drop another $1000 into it...