We're at an early stage of doing this exact thing in Sydney dlvry.com.au
We're not sure how it will work with labour costs and with a sinking Aussie dollar (which will reduce online shopping), but I think we'll learn a lot regardless as a first start-up.
As I mentioned in a different comment in this thread, I feel like it would be a nice value add if you would be willing to have your delivery person call the customer's cell phone when he's at the building (if the customer requests this)
We're not sure how it will work with labour costs and with a sinking Aussie dollar (which will reduce online shopping), but I think we'll learn a lot regardless as a first start-up.