Picked up the monitor and psu on wednesday, just going a cheap non motorised non touch screen monitor for now, will likely upgrade once everything is sorted.
Yes the powersupply has the different voltage rails but not an abundance of plugs which is fine.
Prefer to use my m-ATX board I've got here as I believe the extra PCI slots will come in handy when I decide to put some cameras in the car.
Have pretty much everything I need at the moment, going to butcher an old case to get the slot mounts and use some 16mm MDF I have lying around for the base, back and side and perspex for the top and front.
Using an old IDE 40Gb HDD so if it dies due to vibration then so be it and I'll invest in a solid state drive if it comes to that.
Looking at inputs now, need to find a small track ball and a USB mini-keyboard and likely a USB dvd drive that I will just plug in when needed.
Edit: if you've got a bit of cash and want a comprehensive walkthrough on how to build a particular DIN sized carpc with specific components, I have a book that tells you exactly how to do it. I bought it just to get an idea on how others have done it and while being a bit too basic for me and not entirely applicable, would likely be a benefit to someone willing to buy fancy new stuff to build theirs Also as mine will not be primarily a media centre, I wan't to retain my head unit in one of the three din slots I have so am not building an "in-dash" PC.