No - this is not possible.

Most low end scanners (ie not for professional use) cannot be used over a network connection.

Some printers can be used over a wireless network connection with the use of a print server. However, the cost of wireless print servers (several hundred dollars) will probably deter you from considering this a practical solution. If you wait a year or two, Bluetooth-enabled printers might be available in larger numbers at a reasonable cost - a solution which would provide wireless printing at a much lower cost than current wireless network based solutions.

I guess I should have been more specific - in direct answer to the question from "thespleen", there is no device that makes it possible to connect a USB hub wirelessly to a Mac. And as I indicated above, most (but certainly not all, as "aquaman pointed out) low-end scanners are not shareable on a network. What also needs to be made more specific - to make a scanner shareable it of course needs to be cabled directly to one Mac on the network.