Hi.

Unfortunately, hard links would break on two-drive empegs since hard links can't exist between two filesystems.

Actually, it wouldn't. Hard links don't take up any additional space, only additional inodes (which are available even on a full music partition usually). And the tag file can be stored on a different drive than the data file AFAIK (I didn't actually test this, but ISTR having seen a pair of *1 & *0 files spread across both drives in my MkII). And on my (full) first drive, there are still 500 inodes free, on the second drive, I still have plenty of them too, along with approx. 4GB of free space.
Just in case you wonder: I added the second drive only a month ago, and I added and deleted a few audiobooks since.

Also, I don't think RAID would make sense (yeesh, I think I _always_ misspell that word) on an empeg. With RAID and two drives, only striping mode (Raid 0?) or mirroring is possible. Mirroring wouldn't make any sense at all, and with striping, you would loose _all_ your music if one drive fails. With the current solution, you only loose half of it (with two equally sized drives).

cu,
sven

[Edit: corrected spelling of "sense"]
[Edit 2: Completed rant on RAID]