Thanks for the discussion guys.
Just wanted to give you guys an update.
The delay is somewhat important, I can work with a small delay though. If someone runs up the side of my truck that quickly while I'm merging its their own fault. And I'll have it on camera!
I'm still not sure what cameras to use on the outside of the truck though, due to the weather I drive in, they could experience windchill factors of -40 F in the winter in places like North Dakota, Wyoming, Montana etc.
What about a Software option? I can buy one of those PCs that is basically a Monitor and mount it somewhere, run windows on it and have the live view through it?
I can buy a beasty external HDD system for storage.
I know a few Cisco POE switches that I could install easily in the truck for this application.
Ethernet is a must though, due to the aforementioned issues of space. Running wire is a pain on these trucks on a good day.