There is an range command, but it is only for certain attributes, and port security is not one of them. I found that if you bring up the switch on the network and then use the web interface, the "select all" button works well. I just deselect the uplink.
One other thing of note, the 4500G has spanning-tree edge-port enabled by default, so on your uplink, you may want to "undo" it.
Another thing of note... we're deploying a massive amount of 4500Gs. We found that if spanning-tree (STP) is enabled and port security is set, there is severe packet loss on those ports. 3COM is aware of this issue and is working to resolve it. We've had to disable STP in order to implement port security.