V-twin with a 14,000 RPM redline! We've been watching Aprilia float this idea for the last year or so. If they build it, it probably won't be seen in the US market unless they fit it into a whole family of frames, but even then...
I have a DRZ400s and can imagine the handling is great. I burned off the stock Bridgestone Trailwings with some severe corner carving. I would however like a little more oomph for the more open road. This is particularly true in that the bike seems to work best off the bottom by dropping one tooth off the front sprocket dropping the top speed about 7%. I am sure the DRZ SM is a nice effort, but it is not clean sheet. Now if they put the RMZ450 motor in it I think they have it.
"Ummmm, the death of two-stroke offroad (and street) motorcycles is most definitely not the result of consumer choice. It is plain and simple govt mandate. "
I am not convinced of this. I remember seeing RG500's languishing in showrooms in Germany in 1986 because the release of the GSX-R series stole all their sales. And, yes, I was a fool for not buying one at a substantial discount.
Also, the prevailing sentiment amoung the dirt riders I encounter is that they prefer the easy power characteristics of four stroke dirt bikes. The only reason two strokes were selling in quantity is that they were necessary to be competitive. The advent of lightweight 4 stroke dirt bikes sealed the deal.
I believe that there are no actual regulations or laws preventing the importation of two strokes for closed course competition. There ARE rules for emissions and noise for vehicles used on public lands. If the manufacturers believed that they could make money developing and selling a two stroke streetbike that met these requirements, then they would do so.
An example can be seen if you look at availability and prices of the KTM offerings. Despite consistently doing very well in magazine tests and actual competition, KTM 2 strokes are priced below, and are much more available than their 4 stroke counterparts. The 4 strokes, especially the EXC series, are consistently sold out. Given a choice, consumers are buying the 4 strokes.
Is this a good thing? That's debateable. I have heard that KTM will end production of 2 stroke off-road bikes in the near future. If this is true, they will be missed.
I'm not sure I agree with your generalization of 2 stroke performance, either. If you've been reading Alan Cathcart's reviews of his rides on GP machinery in years past, then you know that 2 stroke 500 GP bikes were measureable harder to ride at speed than the current generation. True, there is a displacement advantage, but do you or I really care about displacement? This begs the question: "What would a 990cc 2 stroke perform like?"
Also characterising 2 stroke engines as fuel inefficient is not necessarily true. Engines can be tuned to perform in various fashions, as their designers determine.
I wouldn't be so convinced of this if I hadn't been hearing people and reading magazine articles touting the return of the four stroke dirt bike for 30 years.