Cut pound cakes into 1/4 inch slices, then toast for 12 min in a 350 oven. Set aside.
Whip 1 C heavy cream. You want stiff peaks, but don't go over into making butter! Refrigerate until ready to layer your tiramisu.
Beat together cream cheese, pumpkin, 1/2 C heavy cream, sugar, pumpkin pie spice & vanilla.
Mix coffee and spiced rum in a measuring cup.
-n a 8X11 pan (or a trifle dish--but then you'll probably wind up doing 3 or 4 layers) cover the bottom with pound cake, brush with a generous helping of coffee mixture, then spread 1/2 the pumpkin and 1/2 the whipped cream. Repeat.
Sprinkle some pumpkin pie spice on the top of the dessert.
Chill 6 hours or more.