I've done this before on smaller scales. Writing a set of table-valued functions that expose the event data in relational form "as of date given by param X", an

I've done this before on smaller scales. Writing a set of table-valued functions that expose the event data in relational form "as of date given by param X", and views on top of that where X is set to getdate(), you get a very ergonomic way to consume "current" & "historical" data. Materialized views can make querying these more natural relations very cheap if your engine supports them.