well I checked out the stats of a Shard of Khales the other day and it does slightly less damage than a MKVIII bat'lef.
Dunno if the tool tip is bugged or not though.
Doesn't the shard of Kahless lvl up with you? If you're LtGen then that makes this the equivelant of a Mk XI. Which would make it the highest mk batleth in the game exclusive to the KDF... plus [CrtH][CrtH][DMG]x2.