If you haven't already, you should check out "Simple Downloads", which is an add-on plugin for WP Document Revisions by David Decker. From the readme:
Want to offer public file downloads? Just use "WP Document Revisions" plus this little add-on plugin! This small and lightweight add-on plugin just adds a few specific additions to the awesome WPDR base plugin which does all the heavy lifting for you!
For my own projects I needed a new but robust and future-proof plugin with a custom post type solution to replace an old, unsupported download counter plugin. With its many benefits I wanted WPDR as a base foundation for that. Now, that I've finally found my solution, I hope it may help you as well :-).