One thing I miss working in Blender is the ability to highlight a layer in the background in such a way that only a shadow of it’s contents appear in black for reference, but are immune to manipulation until the layer is fully highlighted. Are there any plans to implement such a scheme in Blender?
Instinctive blender
http://www.instinctive.de/instinctive.php?p=soft
Blender with a layer manager. lock etc.
Dunno how up to date this is as it has been on the go for a while I think.
A fork from the standard development.
Chimpoid
You can also set a scene as the background. It’ll be locked and you won’t be able to edit it but the outlines show up if I’m not mistaken. Its in the Scene buttons in the output panel I believe.