Explain to BMW how you ride for the brand and how you really want the 800 cc parallel twin motor in the GS platform. Tell them that it's so important to you that you need to be a test rider. Explain that you love the 1200, but you find a smaller, lighter bike to be easier on the body and the machine. Show them pics of the "testing" you've done on the 1200, that ought to open their eyes(lots of pics of it on its side). You might want to add pics of mods Rob has done to his KLR and explain that this is what happens to bikes that aren't built right from the factory, shadetree machanics get ahold fo them and in the end they don't have the "finished" look the factory had in mind, but the manufacturer's stickers are still visable. Not good advertising. You don't want that for your beloved BMW.
Let them know you would do an around the world trip for them if they need you to.
Or Fairbanks to Tierra del Fuego with an expense account might do it.