Anyways, I've flashed back the older rom, reverse engineered some of sammy's removed code from that advanced wifi menu and realized that they're really only using some standard AOSP hidden APIs. So I've created an app that uses these same hidden APIs. For this app to work however, it HAS TO RUN AS A SYSTEM APP! (i.e. apk file loaded in /system/app/ ) So basically you'll need a hacked recovery (clockworkmod) and you'll need to flash the attached file. It needs to run as a system app because it is modifying what android considers "secure" android settings. And normal apk privileges aren't sufficient to change those. There is probably a cleaner way to do this but I was too lazy to dig deeper into the function all the way up to the kernel wifi driver.
Sideloading the APK won't work!
After rebooting, you'll see a new app in your apps drawer, the app is very simple really:
I've tested it on ICS and JB, seems to do the job ! Now I can finally use these JB roms at work.
Note to rom cooks: please do contact me before bundling this app with your roms.