My name is Daniel Kastner, and I just returned from visiting Malsch Baden Germany which is the ancestral home of my branch of Kastner. I met with a Kastner family still living in the area who are active genealogists. Kurt runs www.kastners.info
It was quite an experience. It seems like my ancestors go back like this. Here in Michigan from North Dakota, From Katherinital Russia, from Malsch Baden. There it gets a little dodgy because a french general named Melac burned the whole area to the ground along with all the records in 1680. However, we have a theory that the Kastners in that area originated from Kuppenheim, and also before that Vienna. I took a DNA test and was directly linked to the Malsch Kastners.
To go further though, we need a sample of DNA from a Kastner that is descended from a Kastner in Vienna. This would shed a big light on the whole tree.
Pretty exciting stuff either way. Let me know if you can help. Check this out here: http://www.familytreedna.com/group-join.aspx?Group=Kastner