This is a good example of a program that definitely needs more features on a device like an iPad. Make it open, give people options, Google Docs, Amazon S3, Dropbox or local servers, etc.
This data storage/access is one area I believe CAD companies need to not over think. There’s no subscription requirement, nothing locking you in to how you want to access your data. While other companies are developing portals, repositories, cloud servers and vaults for people to store their data within, Rhino is using something free and available to all, Google Docs.