OFX, CSV, XLS, PDF, and whatever other file formats will be supported by LedgerHub:
https://docs.google.com/document/d/11u1sWv7H7Ykbc7ayS4M9V3yKqcuTY7LJ3n1tgnEN2Hk/
This project deals only with the importing and filing various downloads from institutions, for Ledger, Beancount and other double-entry bookkeeping languages. The import functionality is to a large extent orthogonal to the various reporting operations supported by Ledger and Ledger-like implementations. You're welcome to comment on the design doc above with new ideas and suggestions. The general idea is to largely automate the extraction of transactions to text input.
I'm making good progress on LedgerHub (I have already ported all of the Beancount importers but there are still some dependencies to be removed) and am hoping to release something a few weeks after tax season is over.