YKYAEM if you've been checking out other people's taillights in traffic, trying to find ones to stick on the back of your boat tail.
The Saturn SL || SC has a three-bulb cluster like the Tercel's, but smaller. I think what I'm looking for is something that's not much taller than a license plate.
As for the thread slowing down, I'm pretty much satisfied that we've come up with a good design with an equation that partially describes its geometry. I'm just going to procrastinate until spring, then I'm going to try to get the thing roadworthy in a weekend.
A few details still need to be worked out. Opening the hatch requires maybe 20lbf depending on the temperature and condition of your hatch shocks. That's probably too much force to apply to the spoiler, but I wonder if there are any good attachment points for a handle behind the third brake light.
I thought of something else that the transom needs: holes! I believe this picture shows one of the two primary air exits for the passenger cabin, and I suppose there should be holes of comparable size in the transom and/or on the underside of the tail.
Another feature I'd like the Insight to have is a push/pull handle. The easiest way for me to move the Insight in and out of the garage is by pushing/pulling it. I've been popping the hatch and using the back of the car as a handle, but I'd like something easier to grasp. Maybe I'll find room for a handle on my tail extension.