Feature automatically reverts on cache clear
This is not supposed to happen, a cache clear should not have any effect on overridden features.

I'm just guessing here, but have you tried to uncheck the option 'Rebuild features on cache clear' on the features settings page (admin/structure/features/settings)?

Rebuild and revert are two different things where rebuild should leave the overridden features as they are, but who knows? It's worth the try.