a bit random, but anyone see the last 'inspector morse'? he basically directs everything from his deathbed, i could maybe see granny or vimes doing something like that as a grand exit but i still dont think Pterry will kill either off. And isn't Carrot already sort of taking over from vimes? a vimes Mk 2 isn't really needed if he's going to get killed off.
I agree with tiffany taking over from granny though, maybe granny finally swallowing her pride and asking her to help with something... after all she's thought it was her time before now...