I’ve released the Mortal Kombat “beta” for Sega CD over at ASSEMblergames.com. Not much is known about this aside from the fact that it’s on a Sega Mega CD-R disc, which were primarily used for pre-production builds. I’ve compared the file dates with the final version (including the European and semi-Japanese releases) and they all match, so I’m at a loss as to when this was actually produced and how it differs from the final build, if at all.
UPDATE: This is not a beta. A CRC comparison shows that it is in fact the final build. Bummer.