Hm, I hope not.  How it's meant to work:

  * find_local_directories returns a bunch of paths like ['/path/to/aspace/plugins/plugin1/frontend/views/layout_head.html.erb', '/path/to/aspace/plugins/plugin2/frontend/views/layout_head.html.erb']

  * Each one is checked with File.exists?

  * If there, render :file => layout should load the file by absolute path name

So any plugin can provide a layout_head.html.erb, and they should all get inlined at this point.