Are there any ways to access iCloud-based files with Ubuntu?

I have various Apple products which sync with iCloud.

Are there any ways to access iCloud documents with Ubuntu (for clarity, I'm not asking about email, calendaring, etc.) apart from the web-based access at https://www.icloud.com/?

The ideal option would be a daemon that syncs with iCloud in a similar way to how Dropbox does. However, a programmable API or GUI-based solution would be good too.

Essentially I'm looking to investigate the options; I appreciate they are likely to be reverse-engineered and not 100% official or supported.

This would be sort of a hacky way to do it but, you may be able to install the Windows version of the iCloud desktop manager through Wine. This would give you complete iCloud access on your Ubuntu machine. I know there have been some problems with Ubuntu One so I can understand the need to use iCloud.