Thank you for your suggestion! We will consider AirStash (http://www.airstash.com) for work with in our future releases. Invite more friends and app users to vote for this feature too -)
If you would have a download from webdav-option or http-option, you could download it directly from the Airstash or any website. Then you wouldn't need iTunes anymore for maps. Using webdav in other programs and then move it to Galileo is not really an option because of the sandboxing in iOS.
Galileo Offline Maps
All the ideas and discussions
Allow access to offline maps via AirStash