yeh i have not heard of a new DD in the works but im not sure we will ever know unless they specifically want us to know. they seem to have had good success with the simucube 2 bases, im sure a simucube 3 will have come around in conversation but really i dont think there would be any need for a new set of bases while there is still plenty of room to improve the current lineup and with constant improvements to the software i think we can rest easy support for this hardware will remain for many years.
even if a 3 came out it certainly wont make previous hardware redundant, anybody today using a direct drive is using the best available hardware, be it original simucube devices or the simucube 2 ultimate, everybody will be getting the prime advantage of direct drive and until that changes and new hardware for this hobby surpasses direct drive we have nothing to worry about.
i know where you are coming from though, imagine buying an ultimate with a simucube 3 ultimate around the corner, that would really suck but yeh no… granite are on to a winner with the current bases, comfortably one of if not THE best bases on the market with very strong and flexible software, i see no reason they would need anything new right now… ofcourse, fanatec has shown the success a lower power wheelbase can have so i wouldn’t be surprised if something like that could come into play, who knows. enjoy your hardware.