It took me ages to find these and many over the net are asking the same question.

Where are the save game files for the The Witcher under Wine ?

Answer : They are not in the Wine wrapper.

Save games are stored here.

Goto your local Library under User.

Library/com.cdprojektred.TheWitcher/The Witcher/saves/

Sweet. Thanks for the tip. Played halfway way through the witcher 2 on steam before I realized I had 30 gigs of saved data so for the last 2 days I've been trying to hunt down my witcher save files before the mega monster becomes a giga beast.