Another option is the Buffalo Terastation--its a NAS that can be configured as a RAID 5 drive (mine is). I also gather it will run slimserver, although I haven't tried that.
I use my Buffalo to store all my Apple Lossless files (//elvis/My_Music/Artist/Album/song.m4a) and also have a separate directory of duplicate AAC files for iPod use (//elvis/AAC_Files/Artist/Album/song.m4a). Because you can't tell ALAC from AAC from the file extension (.m4a in both cases), if you have multiple copies, you won't be able to tell which is which from a squeezebox. You also can't easily eliminate a class of songs from slimserver--hence the two directories (slimserver can be directory specific).
I use my Buffalo to store all my Apple Lossless files (//elvis/My_Music/Artist/Album/song.m4a) and also have a separate directory of duplicate AAC files for iPod use (//elvis/AAC_Files/Artist/Album/song.m4a). Because you can't tell ALAC from AAC from the file extension (.m4a in both cases), if you have multiple copies, you won't be able to tell which is which from a squeezebox. You also can't easily eliminate a class of songs from slimserver--hence the two directories (slimserver can be directory specific).