Is there a way to configure Architect to compile .htm and .html files the same way that Appbuilder does? It would also be nice to have the editor behave like appbuilder as well (shade the speedscript section and color code keywords).
There isn't anyway to have mixed languages in the editor at the moment. I suggest you install an html editor from the Eclipse Web tools project so that you can get color coding for html.
To compile them just at the .html file extension to the build preferences. window->preferences->OpenEdge Architect->Editor->Build.
There is code in the builder for OEA to handle them as speedscript files if they have the .html file extension.