KTM, Aprilia and, I believe, even BMW, have these things under development and/or for sale in Europe too. If I recall, the BMW verson had a R1200R engine and hauled a**!
The last few issues of Cycle World & Motorcyclist have contained articles and pics about some of these contraptions. I'll try to check them later and see if I can pull some more info.
Very interesting.....
:-?