That's always been my issue with Financial Reports, Business Rules, Planning, HFM, etc.
You could, I guess, go down the path of automated LCM extracts and apply versioning to that, but you are bringing a lot of moving parts into the mix.
Or I suppose you could hack the tables and bring out the objects but a lot of them seem to be stored as BLOB fields that then get translated at the application layer. Some tools are, I think, now storing the object as XML, so that would be somewhat easier to extract and version.
I think when the objects to be tracked are discrete files it's straightforward, but so much of what passes for EPM now is now relationally stored.
Last point -- some tools have versioning built it but it's inconsistent across the products.
I'm sorry if I'm not helpful on this -- it has been a desire of mine for some time but I haven't seen a clean way to do it.