How to create a build only from new or modified files in a workspace or Stream since a specific date?

I think the general approach is to use the compare command to generate your list of changes.  In our case, we use the auto-generated snapshot (the snapshot created by our Jenkins process) and compare that to the target stream (the workflow target).  If you use the -j option to the compare command, you get output that is very easy to parse programmatically.  At that point, just copy the items that you want (i.e., those that show up as differences in your stream) and process them accordingly.

 Thanks Andy!