[NeilBlanchard]

Please read the Riley page on 3 wheel dynamics that the OP linked to. (I first saw that page about 6 years ago.) The Cg is absolutely critical on a 3 wheel design - if it is too far back and/or too high up for all driving conditions, then they will be unstable.

As you mention in point #3, a reverse trike has the potential to greatly improve the aerodynamics, with the sides tapering in - which by the way would also improve the Cg as well as the Cd. But, a 4 wheeled design can also have a narrowing taper (see Dave Cloud's Dolphin) but avoid the stability challenge.

The Dolphin does weigh a lot - it carrying a ton (almost literally) of lead acid batteries and the structure to support it. But if you put a lithium pack in it with the same capacity, it would weigh about 1,500 less. The Dolphin chassis without the batteries is about 1,200 pounds, which is probably similar to the CR-X trike in this thread with it's engine in place.

The Dolphin is also one of the lowest aerodynamic drag cars I know of. It is also one of the most efficient cars that I know of; despite it's weight. If you build a trike, but do not take full advantage of the format, and/or you don't avoid the pitfalls of the layout, then why do it?