http://niftools.sourceforge.net/forum/viewtopic.php?f=4&t=2683&start=135

Nifskope development seems to be a month out of use now.

I noticed that AlitheLord is taking a look at the 3ds max plugins, so all the best Ali, I hope you get somewhere with it. If you can make a working exporter then you'll be a forum hero.

All in all though, nifskope still seems to be incapable of simply saving a working skyrim mesh without all kinds of sorcery.

http://niftools.sourceforge.net/forum/viewforum.php?f=38

Is development happening elsewhere?

Make sure you grab RC6, that's the most developed version so far, isn't perfect but it does allow you to open/save most of the Skyrim meshes.

Niftools forums is the only place I think you'll see any development for Nifskope.