Let's say that we wish to store the documents sent to us via all of our Customers, and that the documents could be in PDF, spreadsheet, RTF, plain text, Comma-Separated-Values and XML.

It would be hoped that %Stream.Object would be a good choice of property to hold these documents, especially as you would expect %Stream.Object to morph between BINARY (for PDF, spreadsheet, RTF) or CHARACTER (for plain text, CSV, XML) depending on which type of stream was being persisted.