The latest SBSettings 3.0.13 has an option under the More settings to show the wifi ssid on the status bar. Enabling this doesn't do anything for me. Does it work for you?
I've upgraded to 3.1.0 and figured out that if I enable both the date/time on the statusbar as well as the ip address, it also shows the ssid. That seems to be the only way to get it to show up.