A particular pain point that I've had managing websites and services hosted over a hodgepodge of shared hosting accounts and VPSes is centralized and secure backup of web content and databases. AKA, I can schedule complete backups of the source files and database contents across multiple hosting accounts.
While some hosting services have their own internal backup systems, and there are a number of local backup clients you can run, the market of cloud backup service providers that offer a backup-everything service seems to be pretty sparse.
Of course, the major caveat is that in order for such a service to work, you must provide them with credentials to access all of your servers. While services like Mint seem to have slowly made more people comfortable with this idea, it still feels "wrong".
What solutions exist for this problem? Has anybody had experiences (good or bad) with cloud backup providers like dropmysite.com or similar services?
You need more storage and it's more labor to setup, both of which could be impractical depending on the systems you manage, but the central service would have no access to anything confidential. Also, integration between the central backup and the variety of local hosts would be greatly simplified, with no file locks, database backups, consistency issues, backup window coordination, etc.
EDIT: Also, the granularity of available recovery points might be limited, at least from the central service. Block-level backups (and the associate recovery points), for example, could be implemented locally but might be hard to implement on the central service.