Not researching this surname but a listing for GEISZT shows up in town of Dombovar which is in Tolna megye same as where Bonyhad is.
http://tudakozo.matav.hu
www.matav.hu/english/index.html
www.rat.de/kuijsten/navigator
http://vivisimo.com
www.google.com
www.imrehun.com
The 1910 Hungarian megye map is at :
http://lazarus.elte.hu/hun/maps/1910
18 Geiszts passed thru Ellis Island port to America. Might want to take a look at those manifests for possible distant relatives.
I have an Erzsébet Geiszt in my family she lived from 1858-1930. She is from that region. She could have lived in Bonyhád, I just don't know it. Could you give me more information on your family?