Thanks this is a great topic.

One thing we would LOVE is the ability to see repeat customers/shoppers automatically!

So, perhaps if they have already bought say once in the last 12 months this information would be either able to be viewed with the click of a key, or their id would automatically pop up when checkout is happening. This could then lead to some questions being viewed by the seller, say " would you like to make a special offer to this repeat customer?" If yes it then could have some options for the seller to choose from, or they could set up their own parameters, like free post, (we don't currently use free post) special reduced post offer, discount on items, or add a voucher for next purchases. There are probably many different permetations that could be put together and used.

This might help with getting and keeping return customers, and save "de leetle grey memory cells".  

Just a thought to throw into the mix, and is a particular bugbear of ours.