I use walmarts site2store some times; I would use it more if they would allow me to use it for groceries (they don't let you use it for 'perishable' products).

There's a walmart near me that has been testing this. And it is essentially a drive thru. You place an order online (its for groceries, so yes you can order perishables), and have the option to either drive to the store park in a designated parking spot and push a button, an associate brings out your order, OR, they'll deliver it to your home.