I picked up extra wood coffee stirrers (during my daily trip!) at Starbucks and glued them to the back of each number with wood glue. Next I soaked some floral oasis in water (you can buy a block of oasis from the floral department of most supermarkets) and fit that into a steel rectangular container I picked up at Restoration Hardware a few years back.
If you'd like to copy this idea but don't have time to order wood numbers and have them shipped before Rosh Hashanah, you can use house numbers from the home improvement store--just glue them to wood sticks or skewers. The flowers can be purchased from the supermarket and you could use four flower pots instead of one long rectangular pot. It's a fun way to remind your guests the new year on the Jewish calendar!