I'm already using multiple gmail accounts for larger storage for files, pictures and webspace. With the way it is setup, I don't see how you could ever run out? When I want more space, I just send myself another gmail invitation, giving me more mail (file) space, pic space, and web space.
I have an account structure like
X.Y@gmail.com. For the additional space "domains", I just create an X.Y.<subspace>@gmail.com, or you could do <subspace>.X.Y@gmail.com. Right now, all of my photos are being stored on picasaweb. I figure it's safer there than on my own hard drive
