One, I don't think think there is a time limit.
Two, I can't believe you don't use much clonidine. If this happened to me, I would be digging out of it for over a year.
Microsoft uses Volumn Shadow Service to take snapshot of their server, mainly to make point in time copies of databases so they can be backed up properly. Since, you set VSS on whole drives, they affect all of the shared folders. This means that your OS (if Vista or above and any server 2003 and above) will automatically have shadow copies (if turned on) of your data. If you have a lot of hard drive space (and you can direct the shadow copies to very large drives), you could even set up one hours copies for two or three days. While these don't replace backups, they are very nice for situations like these.
Here, you could have stopped the presses, and restored a version from 45 minutes ago once you decided you didn't mind losing x amount of notes and messages, all of which could be re-entered. Where this is especially helpful is if you corrupt your whole database. You could be back up and running in under 10 minutes rather than going to last night's backup.
http://technet.microsoft.com/en-us/library/ee923636(WS.10).aspx
