I did several custom coding modules for this already in place store, namely for admin a module that shows the 3 addresses saved with an order in the right hand bar when highlighting an order. You can not only see at a glance if customer address, shipping address and delivery address are the same but you can also search for all 3 address group items, like street name in any of these 3 groups. Also in admin, I added a cross sell module with my own search hack, so items you'd like to cross link can be found quickly.
For catalog side, I added a shipping module for in home delivery that adds a surcharge to the current shipping module. As payment module, I modified the authorize.net module by adding CVV. This client uses the master products contribution but prefered input boxes for quantity instead of the dropdowns shown by default.