InfoPath has a feature called "merge forms" and it is much better supported in InfoPath 2007. I have not played with it in a very long while so I cannot give you a specific example, but basically you can merge any number of documents into one (merging with code allows you to do it even when schemas do not match, that is, when the target document is based on another form template than the documents you are trying to merge). Once you have the data in, you can do whatever you want, master-detail is fine.
Note that once you've merged there is no going back, that is, changes made to the data will not get persisted in the original 60 documents.
Here are a couple of articles on merging:
http://msdn2.microsoft.com/en-us/library/bb251003.aspx
http://blogs.msdn.com/infopath/archive/2006/10/19/aggregation-and-many-became-one.aspx
One warning/note: merging is a pretty advanced feature...
David Airapetyan / Software Services ArchitectQdabra® Software / Streamline data gathering to turn process into knowledge