Discreet HD (1080p) cameras for 4ch HDD DVR

[sludgeguts]

If you want 4x FULL HD at 30 FPS, you need one of these: http://www.everfocus.com/HQ/Products/Product.aspx?productModelNo=420
The cameras that go with it are surprisingly small, but still massive compared to most dash cams: http://www.everfocus.com/HQ/Products/Product.aspx?productModelNo=461
Then you need a lens to go with each camera, and an inverter to power the DVR.

I wanted to build this for my car, but it was far too expensive.

The DVR I have connected to my cable/TV uses a honking big transformer to drop mains voltage (240vac) down to 12vdc. Most electrical appliances in the home use transformers to drop mains down to 12v or less - In winter, these transformers probably keep the ambient temps in my house above freezing

 

[Dashmellow]

If you want 4x FULL HD at 30 FPS, you need one of these: http://www.everfocus.com/HQ/Products/Product.aspx?productModelNo=420
The cameras that go with it are surprisingly small, but still massive compared to most dash cams: http://www.everfocus.com/HQ/Products/Product.aspx?productModelNo=461
Then you need a lens to go with each camera, and an inverter to power the DVR.

I wanted to build this for my car, but it was far too expensive.

Ultimately, I think this would be a poor choice regardless of cost, camera size or power supply. The available cameras are simply not optimized for dash cam usage, especially at night where they would become more or less useless in capturing what a modern dash cam is capable of (at a fraction of the cost and size). Remember, CCTV systems, even 1080p HD ones are designed for fixed camera placement. At night they mostly rely on IR illumination and they are ultimately not really optimized for capturing fine details of fast moving objects. One of these days I'm sure we will see a high quality miniaturized automotive multi-camera DVR designed similarly to a CCTV system and there have been a few stabs at it so far but it just hasn't happened yet.