"Ya know that does sound good but I cant recall ever hearing of a pumpkin wash for distilling. I've heard of pumpkin beer and of course you could make a pumpkin wash with cans of pumkin puree and add the other items you mentioned to taste, but if you distilled that wash I bet the flavor that you are after wont come over in the distillate very well.
I dont have a recipe for you but if you decide to try it - it may go something like this....

5 gallon PP wash
Pumpkin pie mix in the can ( prolly 5-7 big cans-flavor to taste)
8-10 lbs of sugar (for the likker component)
3-4 pakcages of bakers yeast (Fleishmans or whatever you find in the grocery store)
if you have some enzymes use em...if you dont use 3 beanno tabs and a squirt of lemon juice

Heat up 2 gallons of water and get it to steaming no need to boil it, add all the goodies to your fermenter and pour the water over it and mix very well, DONT ADD THE YEAST UNTIL ITS COOLED BELOW 85F.
Add the yeast and let it ferment. Ferment on the cooler side like 70-75F.This will prolly take 12-15 days.

Then still it on the faster side so it will push or pull the pumpkin flavor out of the wash and into your distillate. Use a goose neck tower (some say pot still) because a reflux tower will remove all that flavor you just worked so hard to get. Now I have never done this before but in my mind if its gonna work this is pretty close to a working recipe. Let us know how it comes out."

After reading more, and hearing what you said about flavor not coming through on distillation, Ive found a recipe similiar to how apple pie is made using a pumpkin simple syrup

Ingredients
1 cup water
1 cup sugar
4 cinnamon sticks
1 whole clove
1 teaspoon ground nutmeg
1/2 teaspoon powdered ginger
1/2 teaspoon vanilla extract
3 tablespoons pumpkin puree (see note above)
3/4 cup vodka
Procedures
1
Bring the water and sugar to a boil. Reduce heat to low and add cinnamon, clove, nutmeg, ginger, vanilla, and pumpkin puree and simmer for 10 minutes. Remove from heat and let cool for 15 minutes. Strain through fine mesh strainer lined with cheesecloth, pressing with the bottom of a ladle to extract as much liquid as possible.

2
Once syrup is cool, mix with vodka and let rest in a sealed glass container for a minimum of two days. Store in the refrigerator for up to 3 months.

No, you were right. I was looking to run a wash and distill. I decided against that when you posted the flavor probably wouldnt come through