The bobcat plate is available from several sources and can usually be adapted to fit most any of the older type mounts. There are some available that may even bolt on.
Here's a couple plates for you to give you an idea. There are threads here with the drawings and dimensions for these plates and there may be pictures in the media section.
http://www.skidsteersolutions.com/Skid_Steer_Universal_Quick_Attach_Adaptor_s/64.htm
http://www.buyattachmentsdirect.com/skidsteerattachments/quick-attach-plates/