Don, I'm sure those two sidewinders both pre-date Gene's car, but using the motor as an integral part of the chassis was actually pretty common at the time, both in cars like these, and in inlines that just have front and back ends bolted on...
What's more interesting, in my opinion, is another small series of cars that I found. I've got a GT, sport and F1 cars, and all have this type of midwestern sidewinder chassis, but in which the motor has been cocked over a few degrees to fit in easier. These seem to be from 67-68, but I don't think they are real anglewinders, because a lot of effort has been made to keep the track narrow, following Pete Hagenbuch's methods of screwing the gear to the wheel, set screw under the tire, etc. But the builder still angled the motor very slightly for it to fit in. The first one here is from a Ford MkIV GT Chassis, and the other two are from a chassis for a 50s Maserati F1:
Here's another one I like a lot, that uses the traditional method to combine smaller wheels, slightly narrower track, etc. in a 1/32 car: an idler gear! But this is a custom-built job, and very nicely done, much better than it looks in my mediocre photos. Lots of movement on the chassis as well... And in spite of being a Thingified Ford GT, there's still lots of effort to make this a very presentable car, including a full cockpit!
A last toad, that I tried to turn into a Princess, or at least a lady in waiting...First, as found (a pair of Cheetahs in fact), then as I modified it using a different body... And yes, it uses dual friction drive!
Don
Alpha was cool too but hey I guess that what it's all about collecting old stuff? 
