I have a family tree of nearly all the Dürrenbergers from Switzerland.
The tree starts with 2 Dürrenbergers in 1550 from Reigoldswil. It was created by a professional Geneaologist and a cousin gave it to me. (I am a Dürrenberger)
Anyone interest please send me an email and I will send it to you. There are about 8 pages.
by several of the names there is the remark "Ausgewandert nach Amerika" (emigrated to America".

My email address: cosi@swissonline.ch

I hope I can help you with your searches.