Yes this works quite nicely with an organization with multiple sites. The dhcp server location isn't determined by the SSID, it's determined by the device that's doing DHCP relay for you, which can be the switch or firewall at each site. The DHCP server is smart enough to see which subnet the request came from and respond accordingly.
One thing to be aware of... if the locations are close to each other, make sure the DHCP lease time is less than the time it takes to get between locations. Windows 7 has this 'helpful' feature where if it sees the same SSID it tries to keep using the same address without going through a full DHCP cycle. That one puzzled us for a very long time....