With the new release of the MonoMac add-in for MonoDevelop, you can easily turn your Mono application into a full Mac bundle, and you can also get a Mac installer for your application with all of the Mono dependencies bundled with it as well as creating Mac applications for distribution on the Apple Mac AppStore.
The MonoMacPackager no longer exists, and has not existed for a few months. We basically granted a license for appstore distribution to anyone that requested the license for AppStore distribution, since we did not originally have plans to build a product.
Now that we are launching a product, we offer the license as part of Xamarin.Mac.
OK, that makes sense. I mean, for an independent developer, that sucks, because it's honestly not worth $399 to me (I'd be happy to pay for it in a corporate setting like we do for MonoTouch, because of the support stuff, but for personal-project stuff I just can't rationalize it), but I get the reasoning.
Is the licensing for MonoMac/MacCore remaining as-is?
1. Xamarin.Mac comes with a commercial license, so you can ship to the Mac App Store (not allowed under MonoMac's LGPL license).
2. Xamarin.Mac comes with commercial support.
3. Xamarin.Mac includes bindings for several new APIs, including CoreBluetooth, GameKit, StoreKit, SceneKit, and the new Mountain Lion AppKit classes.
You can see a full list of differences here: http://docs.xamarin.com/mac/guides