Nice Launcher, works well on the CM9 Alpha 13 Nexus S ROM. This has some serious potential. A few things I've noticed:
1 - On the homescreen, when I press 'menu' and go to 'Nova Settings', it takes me to the normal settings. I can only change launcher settings from the icon in the top right of the app draw.
2 - The widget selection is the same as Gingerbread. I've gotten used to the ICS way
Great work from the dev. I look forward to more features being added in the future!
EDIT: I just re-read the OP and seen that it needs to be a system app for widgets in drawer!
Phone(s): Galaxy S3 White / HTC Sensation (S-OFF)
ROM(s): UltimaROM 9.0.1 / Frankinstine AOKP JB [Nov 22]
Kernel(s): Latest Yank / ROM Default
Radio/Firmware: XXELLA / 3.33
Network(s): T-Mobile UK (EE)