Not being privi to the back room high finance wheeling and dealing thats going on, we all are going to have to hold our breath until the deal is solid.
Personally, I don't see Ducati keeping any of the Aprillia motorcycles in production. Just would suck to much away from their bike sales. They basically want the boutique marques, and maybe the scooters (though thats not their thing really). They would keep some of the motorcycles going to keep people happy, maybe bring the 450 vtwin motor to production run in some form, but in the end the aprillia bikes are going to be a "red-headed step child" in the Ducati family.
I would like to see Ducati buy the Larverda, and Moto Guzzi lines, then have Aprillia use the Italian gov'mnt to stabilize the remaining company, 1st by repealling the helmet law (I'm no Abate member, but we really fight Darwin way to much).
As far as Ducati becoming the GM of motorcycles, it would take a serious change in corporate though process for Ducati to pull that off. Not to mention the marketing and redesign of the Aprillias bikes to make them more different from Ducatis, as to appeal to a different customer base.
My two pesos