It's done all the time.
The easiest way is to use the customer's ID as the title. This is the easiest way that he and only he will find it.
When I do this, I write my description and post my pictures as usual. Then I list as a Fixed Price / Good Til Cancelled/ 30 Day listing. For me, this is the least expensive type of listing.
I insert the price and shipping I have agreed on with my customer and notify him that the listing is up and give him a deadline.
If he does not pay by the deadline, I add him to my Blocked Bidder List as a timewaster (only had to do this once) Revise the title to something saleable, and the asking price and shipping if necessary and let the listing carry on .
