Zeika is a Japanese Optical brand name combined with “Zeiss”s “Z” and “Leica”s “eica” part (ingenious). It’s a product made in the 1960’s providing the same lens to the US brand, Carl Meyer and Nighthawk.
Zeika Nominar on the E-P1: http://www.flickr.com/photos/chachahavana/3900002705/in/photostream/
Zeika Nominar on the G10: http://www.flickr.com/photos/leiss/sets/72157620574119065/detail/
You can find one single lens on eBay right now (Click here)!