Well Eureka! Foxmarks to the rescue! In fact, it brings a couple new tricks to the table besides allowing for basic FTP/HTTP bookmark synchronizing: if you don't have your own hosting space, they provide hosting for you (for free) to sync your bookmarks with. If that wasn't already nice enough, they also offer the .Mac-like ability to sign into your account and access your bookmarks from any computer through a web interface - allowing almost anywhere-in-the-world access to your bookmarks.
While I just found this extension last night, their bookmark hosting service unfortunately suffered a power outage on Dec. 31st which, at the moment, means you can only use the extension to sync bookmarks with your own hosting service. Rest assured, they're working diligently to open the doors for hosted bookmark syncing, but if you're like me and you have your own space you'd like to use, I can verify this extension works like a charm. Sync away!