I've listed my Gitane D-500 that I converted to Nylon string on ebay (it will accept Argentines as well without any conversion). It has a crack, which has been there forever, but does not affect the playability. It's also an early model #60 with the Satin finish (I don't think the top is Sitka) it actually looks more like European Spruce...it has that nice antique yellow-brown patina it has aquired over the years. If you take the bridge off you can see the original finish was really light, and has darkened with age. It sounds like a cross between a classical and a Gypsy Jazz guitar, with a loud voice.
It's on ebay right now:http://cgi.ebay.com/Gitane-D-500-guitar-Classical-Nylon-acoustic-converted-/170629563679?pt=Guitar&hash=item27ba50851f