0_namespacing.scss

mymodule {
  @at-root {
    .#{&}-header { ... }
    .#{&}-footer { ... }
    .#{&}-body   {
      a          { ... } 
      span       { ... } 
      p          { ... } 
    }
  }
}

1_namespacing_output.css

.mymodule-header { ... }
.mymodule-footer { ... }
.mymodule-body a { ... }
.mymodule-body span { ... }
.mymodule-body p { ... }

Please keep in mind that these feature can be used within mixins that accept content blocks, etc. So an "@include module($name) { ... } " concept could be defined very easily. I think we will quickly find some very nice ways to create useful abstractions with this set of features. And as I have pointed out elsewhere, the @at-root directive and script access for & have benefits beyond just modules.

Has there been any discussion to do something more unobtrusive? For me, the value of namespacing comes in when integrating, where it's not possible or edit and maintain the source. For example, bootstrap and foundation both use .table which to me is too generic.

With styles.css:

.table {
  color: red;
}

Then

namespace mymod {
  @import "styles.css";
}

Would compile to

.mymod-table {
  color: red;
}

Can someone please give another example of how namespacing might be used--thanks @aceofspades, I just would like to see it in another context.