Natively, no. Not at least any way that will be very reliable.
You can accomplish this with 3rd party tools like ExpanDrive, though. I have a few clients using this to mount an SFTP server and give it a drive letter.
I'm sure there's other similar products that are cheaper or free (ExpanDrive is $49 for a single user license), but this is all I've used.
My GoogleFu finally worked.
Expandrive does this now.
As does NetDrive.
I leave the post here in case someone else needs to know.
Use app like ExpanDrive on Mac OS X. http://www.expandrive.com ExpanDrive will mount your cloud drive (many cloud services are supported like DropBox, OneDrive, Google, even FTP, and many more) as new drive on Mac. You can create folders, and drag and drop files to copy to cloud. If you create multiple free cloud services accounts, and mount them all, you end up with lot of free cloud storage for your music.
As those ExpanDrive mounted cloud drives act like regular discs on mac, you just drag and drop files (or folders with music) to iTunes (or any other player on Mac) and play them like any other files. I am not sure if iTunes has file cashing to avoid network play skips if your network is slow. But in that case you can use audio players like Audirvana Plus that use RAM caching for playback. http://audirvana.com
You might try free apps from http://www.zibity.com, I have not tested them so I am not sure if it will work.