Design of the 450X.
I would suspect that the BMW will be based on the model riden by Frans Verhoeven. Central tank etc.
The new BMW/Husqvarna effort for Enduro/Motocross will use the BMW engine with a newly developed Husvarna frame and suspension, husky plastic. Yes the sprocketshaft again on the swingarm pivot for better traction and constant chain tension, the same as the BMW. This bike may be used as a platform for future rallies but I would think that time is too short to get that bike out and tested and rally prepped for the Dakar. The bike is not yet in the showrooms. TE449,TE511,TC449.
PS the engine is made by Kymco (Taiwan) to BMW spec's and tolerances. This has caused for some tension in the factory in Varese. For a 450 it is a fast engine, reliabilty has been an issue, Verhoeven has done a couple of engines last year and in the Challenge but believes that now the problems have been solved. An oil cooler has also been added.