Go to any police tsu and you will find a box of sd dvr, board cams. Bullet cams and assorted lenses. Blacktac, hot glue and a dremel.
That does for 70% of my work.
Longer range or longer duration add a hdd dvr and maybe a watec camera that takes ordinary camera lenses.
Transmission only accounts for a low percentage of jobs and with 3g can be very hit and miss