We aren't planning to provide any additional types of file storage, as we don't believe that the local file system should be used at all in a scalable app, as it creates state at the app server.
We do provide access to /tmp if you need scratch file space for processing (it is not persistent between requests). More info here:
Right now, I prefer to upload to the local filesystem then process and store on S3 via DelayedJob. But I will give this a try.
Are there any plans for add-ons that allow EBS storage (or something along those lines)?