It's now possible to officially compile Xamarin.Mac libaries on Windows which means that ReactiveUI and MvvmCross can now compile for every platform (Xamarin Mac, iOS, Android, UWP, WinRT, WPF, WinForms, WP81, WPA) known to man on a single machine and package up the results in a single step.
This feature is a huge win for framework authors/maintainers and the open-source ecosystem. Martijn (MvvmCross) is in town/down under ATM, over beers we discussed implementing the RxUI CI pipeline into Mvx once this feature graduates from alpha to the stable channel. Our current way of doing releases is to compile on OSX, sync on Dropbox, then compile on Windows and then package. Super painful, both projects have suffered regressions at times as a red/green merge, package and deploy workflow before now wasn't possible.