Got my Blackvue DR400G-HD camera installed today at TM Dania. I would have done it myself (did it on my Range Rover) but the trim is actually much tighter on the S than the RR and so thought I'd better get some help from someone who knows how to remove the trim pieces properly. Glad I did (though it cost me an hour labor)
They ran the cable through the headliner, down the A pillar, under the carpet in the passenger footwell, along the side of the center console area, then up and out next to the lighter socket. For simplicity we decided to stick with the lighter socket and not do a permanent install to the fuse box - it was too much work to route the cable through the firewall.
Works great!! The only downside is the lighter socket is not powered when the car turns off. Might look to tap into a non-switched 12V source - if I can find one.
For those that don't know the Blackvue, it is a full HD, 30fps, 120 deg FOV camera with GPS and three-axis accelerometer recording. It auto wraps recordings on a microSD card (last in, first out), but will automatically lock down (make read only) recordings if it senses high G (settable), on the assumption you've had an accident.
I've got the Original 400G; there's now a Mark II version and a 500 version with wi-fi streaming to mobile devices. The 400G forum can be found here. Originally from Korea it can be a bit cryptic to do firmware upgrades, but it is a great package for the price ($250)