Is there a working extension to import Kinect skeleton data as animation into Blender? I already tried Bloop which would end in rewrite lots of C++ and Phyton code. The issues with bloop are described here im-so-annoyed-im-resurrecting-this-blog.

For other things like RGBDemo the dependencies to OpenNI are no longer available.

It wouldn't be necessary that the import is done in real-time.

Is there any working module/add-on, external converter?
There should be a script for importing bvh files under

File -> import -> Motion Capture (.bvh)

, at least in current versions of blender.

A program to save kinect skeleton data as a .bvh file can be found e.g. on  the following site:
http://tech.integrate.biz/kinect_mocap.htm