Cisco Aironet APs already support multi-broadcast SSIDs and they've done so for a year now or more. You'll have wait till the 800 series supports multi-broadcast SSIDs.

This is why I get so irritated by people who keep suggesting that hidden SSIDs are more secure when they're not more secure. You'll just cause a lot of problems and not get any more security.

I would suggest that you make your WEP network the broadcast SSID since most WPA devices can at least tolerate hidden SSIDs. The fact that devices are still being sold with WEP only is a crying shame.