I ~~am sure~~ hope somebody™ already thought of this. Feel free to advertise your project here.
P.S.: Image transcription:
Patrick from SpongeBob SquarePants gesturing to the left with open hands:
Somebody should take document type conversion from Pandoc and version control from Git
Patrick gesturing to the right in a pushing motion:
And build a frontend around it
If I'm understanding your question right, kind of. Pandoc is only for document conversion though, no spreadsheets, presentations, etc. But at that it can convert between a lot of formats. And git can be used to version and share those documents.