Bit of fun with a manfrotto suction cap (thanks Daniel!). It's incredibly nerve wracking to drive around with several grands worth of camera and lens sitting up front like this.
2 x SB800's on back seat with full cut of CTO gel on each at 1/32nd power. 1 x SB800 with 1/4 blue gel squeezed into dash area at 1/64 and -2/3 power (with cinefoil snoot to keep as much light off top of steering wheel as possible).
Camera triggered by PW on Channel 1 (which had Daniel's Zebra Flash cord plugged from PW to camera), and another PW in hotshoe on Channel 2 to fire one of the flashes in-car and the other two flashes in car on optical slave mode. Using different channels like this meant that one fire of the PW I was holding would trip shutter, and as it was about to close, rear sync mode then tripped the interior flash on another channel which itself pushed the other two into action via their optical slaves.
There is a small ridge down the center line, so I had to mount the suction cup to one side of this, hence the off-set framing - not as squared up as I would have liked.
ISO 400, 1/8th sec, f/8.
Tip for others - a super-clean windscreen if you don't want to spend all night cloning :)
Daniel's pics include some typical set-up shots.