I never heard of it nor tasted it....but I would make a pie shell, put a layer of mincemeat in the bottom, cover it with the custard I use to make pumpkin pie and bake it until a knife inserted half way to the middle comes out clean.
Linda C

I found this one by a Google Search for Mincemeat Pumpkin Harvest Pie-there may be others but this sounded like what you were looking for so I didn't check out the others:
INGREDIENTS:
1 1/2 cups prepared, meatless mincemeat
1 egg, beaten
1 cup pumpkin puree
1/2 cup white sugar
1/2 teaspoon ground cinnamon
1/4 teaspoon ground nutmeg
1/4 teaspoon salt
1 prepared 8 inch pastry shell
1 cup whipped cream

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DIRECTIONS:
Preheat oven to 425 degrees F (220 degrees C).
Beat together egg, pumpkin, sugar, spices, and salt with rotary beater.
Spread mincemeat into the bottom of the pastry shell. Pour pumpkin mixture over mincemeat.
Bake for 35 to 40 minutes. Serve with whipped cream, slightly warm or cool, but not cold.
Hope this is what you want.
RL`

That's what I said, didn't I?? LOL!
Linda C