Since it seems like you are open to suggestions for your new plugin, not sure how you are determining what gets put into your paid version vs free, but I thought I would start a new thread to offer a few ideas of mine more geared towards multisite since no one is really offering a notification bar with that in mind.
1. Multisite - Add the ability to edit the bar on the main blog with an option to show on "all" pages throughout the network (each blog), or maybe just on the homepage of each blog, or both, which would make it it very easy for an admin to flash notifications to all network users.
2. Multisite - Be able to schedule multiple bars, meaning, be allowed to create a few different bars and be able to show them via a basic scheduler for the whole network (all blogs).
3. Be able to add multiple messages on the same bar - maybe use a scroll or some other fancy way to show the messages - including link capability for each
4. Add social icons
5. Allow user to hide the bar, if they choose to, when browsing
6. Simple color changer
7. Critical - responsive, just because the future is almost here
...I'm sure I'll have more ideas over time, if you'd like to hear them.
Regardless, look forward to seeing what your paid version will offer.