This indeed depends on the IDE, just noticed today that the newest version of the free Web Essentials 2012 plugin for Visual Studio has added region support in HTML.
http://visualstudiogallery.msdn.microsoft.com/07d54d12-7133-4e15-becb-6f451ea3bea6
http://vswebessentials.com/changelog
<!--#region main -->
<!--#endregion -->