Has anyone made biscuits with sour cream?

I often use a little leftover sour cream in my biscuits. Instead of my usual 1 cup of milk, I use 2/3 cup milk and 1/3 cup sour cream.

Yes! I used to make biscuits a lot, including scone variations. Sometimes I've found myself without the right dairy ingredients, so I've improvised with any number of combinations of milk, sour milk, milk soured with vinegar or lemon juice, buttermilk, yogurt, yogurt mixed with milk or soured milk, cream, sour cream, half and half, or cottage cheese (which makes really neat biscuits, especially done in the food processor).

I would mix your sour cream with enough milk or soured milk to make the consistency of the ingredient called for, like if it calls for 1 cup of buttermilk, use about 2/3 cup sour cream mixed with 1/3 cup milk and a teaspoon of vinegar.

You'll be fine - I do this often for the same reason, to use up sour cream before it turns into a science experiment.