One in a million is definitely a joke.
Unfortunately, for you the 500 GB model uses two hard drives together as one RAID. If it was only one drive then you could just pull the drive out and put it into another enclosure (a RAID is far more tricky).
If you have the tapes, I agree with Shane, redigitize. Get a replacement from LACIE and just do it. It is a lot easier than the alternative.
If you don’t have the original tapes or there is something you really need on the drive, get a replacement and open it up (this will void your warranty) and swap the drives from your old LACIE to the new one. If you keep LACIE on the phone long enough they might even coach you through it (they did it once for a friend of mine).
The reason I say this is because the logic card (for the RAID) fails a lot more than the drives do. My buddies LACIE has the bridge board go bad for example, the drives inside were fine.
By the way, opening the LACIEs up and changing the drive is not as hard as it sounds.
Those are your basic scenarios. Good luck.
A.