In short, no. Numbers are pre-assigned to phones. Your only option is to go to each 7-Eleven store and ask each clerk to show you the numbers for each of the phones they have for sale.
This site is run by a 7-Eleven Speak Out Wireless customer. I am not a 7-Eleven employee, nor do I receive any compensation from them for providing this site. The goal is simply to share consumer information with others.