I'm usually open to borrowing from the wisdom gathered from a more developed industrial cousin and so I went looking as to how gas motors were mounted.
It appears they were clamped to the seat-tube and used the water bottle mount for "support" against rotation(I suppose, I don't really know). Given how much more standardized the seat-tube is compared to down-tubes I have to wonder why aren't seat-tubes being explored as a possible mounting option? Is it the spinning motor being too close to the legs? Is housing the motor too much of a labor? What is it?
It appears they were clamped to the seat-tube and used the water bottle mount for "support" against rotation(I suppose, I don't really know). Given how much more standardized the seat-tube is compared to down-tubes I have to wonder why aren't seat-tubes being explored as a possible mounting option? Is it the spinning motor being too close to the legs? Is housing the motor too much of a labor? What is it?