I talked with the Engineers on this one, it was interesting as at the time, when Gas was at $4.50+ a gallon, mileage was a REALLY BIG deal.... They said that a few things really drove the gearing, first the loss of one gear for a true reverse, this engine is a six speed in the two-wheeler form. Next was the "revvy" nature of this engine, it really does generate its torque in the higher RPMS, more like the two stokes of days gone by. Also, they were interested in keeping it a sporty ride, hence the low stock windshield. Note that the touring bike engine has been tweaked for more torque at lower RPMS:
"The 2010 Can-Am Spyder RT will still source a variation of the Rotax V-Twin found in Aprilia sportbikes, a liquid-cooled, 998cc V-Twin with multi-port, electronically fuel-injected 57mm throttle bodies. The Spyder RT’s Rotax 991 engine has been retuned to handle the demands of the additional weight of the touring package and a passenger, with three lb-ft more torque coming on at 750 rpm lower in the powerband. To go along with more grunt down low, its gasses will be squeezed at a higher compression ratio of 12.2:1 compared to last year’s 10.8:1. But peak horsepower has been trimmed down, with its top numbers ringing in at six ponies less and coming on 1000 rpm earlier in the rev range. (Claimed 2009 Max Output 106 hp @ 8500rpm - 2010 Max Output 100 hp @ 7500rpm)"
So maybe this will allow for different gearing, even if only via rear sprocket change...