Anybody try Mozilla banners (or any other banner) in widgets?

I'm tempted to just test out some banners in widgets myself. I have about 20-25,000 users in a Hebrew translation widget for iGoogle, which could contain an especially nice group of potential new users since the Firefox usage rate is apparently low in Israel. However, I am concerned about the results of posting banners in small widgets. Furthermore, I am unfamiliar with Google's policy on allowing any type of banner in iGoogle widgets.

Could anyone out there with knowledge and/or experience in widget development provide some insight? iGoogle and Netvibes would be particularly helpful for me to test some banners.

Thanks,
Jeremy