We usually have at least one person who can make a frame quickly for a customer; we just did a rush today, in fact.
During while you wait, customers either browse or they ask where they can get a good cuppa joe. We recommend either the coffee shop down the street, or the new Co-Op down the way. Support local businesses!
One of my favourite stories to tell is the Sunday before Christmas, and a couple visiting from Texas wanted to purchase a Solitude. We had two framed: a large one with just conservation non-glare in a wooden and a small one with a triple mat and museum glass, silver frame. We also had them in stock. They wanted the big one, but framed like the little one. We said we'd have to them by the time we closed.
Complete job: custom frame, triple mat, mount and fit: 45 minutes. That included a v-nail blowout crisis, quickly fixed.
Ad addendum: We DO advertise this service, and before the customer leaves, we make sure we have the supplies to do the job. Usually they are pretty flexible if we don't, but more times than not, we do. It was rush jobs that made us expand our matboard from special order to in stock.