Client workstations will always have to install a driver; what you're wanting to do is have it always install automatically, from driver files stored on the server if it's not a printer already known to Windows. SME 7 can be made to do this but apparently it isn't easy for now. A search of the forums for the following terms:
samba printer drivers store
came up with some interesting threads but it's nothing I'd especially want to fiddle with.