I'm not involved with development, but the issue has been acknowledged in developer meeting notes:
http://lists.blender.org/pipermail/bf-committers/2013-May/040144.html

However, with the 2.68 release candidate out, I don't think anything has happened in that regard.

As for the renderer working with custom normals, I wouldn't call it "support", rather a "happy accident". Indeed, the internal renderer did perform recalculations up until a while ago (I only figured out that it doesn't do that anymore yesterday). This was probably changed with the integration of the new BMesh modeling system. Currently, the normals are just a writable property and all renderers/exporters use it, as far as I can tell.

That's a great side effect from bmesh integration!

- Michael

Cool!
Blender is developing into a really nice program with some really good training available. To make it even better Otay is beta testing OctaneRender for Blender.
http://render.otoy.com/forum/viewtopic.php?f=7&t=33592

Hey, Zalamander! Thank you for this... Something I've wanted for a long, long time. Works great!

Hello
Tell me if I am wrong

All works fine but as soon you edit your object normals are replaced by the Blender normal recalculated !
So in fact you must only use in Blender your imported object without "edit" you can just change the material!

So optimze your object's form outside Blender before the importation! :)

It's yet no so bad! ;)

zalamander said so in his initial post..

Aaaaahhh :)