For what it's worth to anyone, I ended up making my own and it seems to be working ok. I'll get some pictures of it later if anyone is interested. I'm not an electronics expert by any means, but I like to tinker, so forgive me if I don't sound like I know what I'm doing (because I don't).
I took apart 2 USB/Cigarette lighter adapters and unsoldered the power/ground connectors on each. They output 5v and 1amp I believe (didn't test the amps). I soldered in a "Add-A-Fuse" to the positive, and a wire on the ground. Tied the two grounds together and combined them on a post that attaches to the ground for my car. For the output I ended up using battery terminals from my RC truck spare parts so that I could "re-wire" with the usb cable if need be. Directly soldering the two together would be better for long term though.
I had a long mini-usb cable from some other accessory lying around, so I cut off the female end and stripped the wires back. I used my multimeter to trace the wires back to the male end of the mini-usb plug. I soldered the female battery terminals to each of the wires.
For one of the 5v step-downs from above, I connected the positive output to the 5v (red) and ground to ground (bare). For the other other 5v step-down I connected the 5v output to the VCC+ (green I think) wire and ground to ground (bare).
Parking mode seems to work. I don't really know if there's an indicator that tells me if it's working or not, or if the parking mode is being enabled by GPS, but my "parked" recordings are using my 10fps setting.
For what's it's worth, I plan on this as just being a stop-gap. I'm too impatient to wait for the kit and I keep some equipment in the back of my truck that I wanted to keep an eye on, but as soon as it's out I'll be ordering one.