I agree, serious people will wait. I also try to have and think out different places I can have people trying mattresses. It can actually be helpful having more than 1 customer at a time. They can be more ralaxed and willing to lay down if you ask some qualifying questions and then take them to an area to try some comfort choices, And tell them you will be right back to find out which is most comfortable for them. Since you are not watching them, you can often go back and forth between customers. They can see you are helping others and can talk among themselves more openly then with you there the whole time. But the big thing is, usually, if you sell one of the customers, the others there will buy too, if you let one leave, the others will leave (and often for the same reason the first person did). If someone stops in for a frame or mattress protector, I will usually try to take care of them quickly and get them on there way while others are trying a set or having a private discussion about which one to buy or when to have it delivered.

IMO your ability to handle more than one up would be directly proportional to the size of the showroom. If you are in a 50K sq ft furniture store it would be tough to keep more than one presentation flowing. In a 4K-8K sq ft bedding specialialty store it is much easier and most of the time works to your advantage to have more than one up. Everyone knows the domino effect in a sleep store. If you sell the first one the rest of your customers will buy as well.

This is something that I personally wouldn't recommend. The idea behind the sale is to engage your customer from beginning to end. Throughout the sale you are trying to convince the customer to buy from you - taking another up would just confirm to your customer that you just dont care that much about them, therefore limiting your ability to close them yourself or taking the risk that another associate will scoup the deal from you.