The database has been saved by many people I suppose (but not me, sorry) and may be still available; google for "Mt.GOX leak".

The site was http://mark-karpeles.com/ but that URL now points to a form ostensibly created by Mark Karpeles for clients to confirm their claims against MtGOX.  Careful, it smells of a phishing attempt and it may be illegal since creditors should probably contact the bankruptcy court/executors rather than the unknown author of a dubious webpage.