What I obviously don't know is the file behavior of IMAP and how the link is created that is used in OO.
I would presume that if file name is assigned in the IMAP account and what is listed in Mail is a mirror of the file structure in the IMAP account, then whenever the account is rebuilt there is a possibility that the link would work.
But if there is some other information added by Mail upon downloading from the IMAP server, then the link probably wouldn't work.
This is pretty critical in trying to decide whether to link to emails or copy the full email. I use a ton of links to emails in notes created in OO. It is the primary reason I use the program.
Prior to using OO I had a hard drive failure and restored to the new drive from a Time Machine backup. But it did rebuild the Mail account. The settings were all there, but it downloaded a bunch of the mail that was on the server and rebuilt the mailboxes. I don't know what will happen whenever I upgrade to Snow Leopard.
I would hate to have all those links destroyed. A huge percentage of my documents would be worthless.
But it is great to be able to use the links, as they are very easy to create. They allow me to go back to the original email quickly, allowing for replying and forwarding. And all the attachments can remain with the emails and don't have to be saved to the local drive and also linked.
I would think there would be someone who has gone through this and would know how these mail links work. Hopefully they'll reply at some point.