Hi Chris,
there are two sorts of XAML: compiled XAML and loose XAML.
Loose XAML can be embedded also by XIDE (and that is what I already do for some functionalities of my XIDE written WPF applications), but for WPF forms loose XAML has some limitations.
Normal XAML is compiled to BAML by Visual Studio, and the relative compiler also generates a code file (xx.g.cs for C#, xx.g.prg for X#), and adds this file to the project.
Unfortunately the only way to generate that is to use MSBuild, and it has to be an intermediate step in the compile process because the XAML could reference classes in the application itself.
For me this is not really a problem because I build my windows in code, using my own classes that offer some functionalities, like databinding of the DataGridView columns (the columns are defined in the ViewModel, and not in the View), and also the possibility to immediatly implement different languages into the forms.
Wolfgang