Hi Sid,
This left-handed Krieghoff prototype Luger, Serial number 001, made in 1940 shown here:
...is a figment of my imagination (and my graphics software "mirror" capability) <img border="0" alt="[hiha]" title="" src="graemlins/roflmao.gif" />
Just couldn't resist Sid... The answer to your question is that No, I have never even heard of a Left Handed Luger... If anyone offers you one for sale... make sure you get to hold it in your hand before you sign the check.
Definitely an interesting thought though... but for the manufacturing reasons you specified... I doubt it would have even been considered.
Thanks...