Beyerdynamic DT880 32 ohm. Semi-Open is weird, there isn't a ton of semi-open headphones that have all of those features and traits. A headphone that I think closely resembles the Kennerton headphones is the Monolith M1060. $299 + tax, planar magnetic, (idk if that is a problem or not) 50 ohms. A very good headphone. Also take a look at the Monolith M560, a little cheaper, removable cups to make either closed or open, 42ohm, also planar.
Hope this helps.