"Must be a depression/war thing holdover."
No, just common sense passed down from mother to daughter through the generations and sons like me who spent time in the kitchen learning how to cook. Why buy shortening and throw bacon grease away wasting both money and bacon grease?

"Now I could go for bacon-flavored toothpaste."
You don't have to look far: http://mcphee.com/shop/bacon-toothpaste.html

"Imagine the guy who went to bar when bacon vodka was new and he tries it for the first time."
Bakon, bacon flavored potato vodka (must be Polish since that's the way they make vodka) available at:
Southern Wine and Spirits
7600 Richard Street
Columbia, SC 29209
(803) 695-1630
http://www.southernwine.com