Personally I think the ability to browse, open file and play media off the SMB shared is one of the coolest thing in the history of the Internet Tablet. Even though it's not perfect.
I think there maybe a work around on this. I don't exactly have time to work on this, and lacking a good knowledge on this part, but instead of focusing on the n8x0(which is the real problem) to look on protected smb share. I think if we can find out what username/password(blank?) the n8x0 is using in order to try to access the network, maybe we can add temporary username in the share object, instead of opening it to everyone, and possibly less security risk, until somebody find a way to hack the file manager or the next n8x0 update.