DEPRECATED PRODUCT: You should consider using the EpozDocument instead.
You use File objects to host pure HTML content ?
Then you'll enjoy using EpozFile objects in place of File objects.
The EpozFile is a quite good content object to make a lightweight CM if Plone and other CPS are somehow overkill for what you need.
What's an EpozFile? It's just the same as a File (inheriting from File) with the sugar on it : An "Epoz" tab that shows the HTML content in the Epoz WYSIWIG editor.
In addition:
Requirements: Epoz must be installed (0.5.1+), otherwise, EpozFile objects will behave just like ordinary Files.
All user documentation is in the README tab.