Lost messages - can I get them back?

Question

I had an inbox with 300 or so messages from the last 6 months, plus attachments. Then, shortly after upgrading to Snow Leopard, Mail stopped sending stuff (seemed not to like talking to the smtp server), so I fiddled around and created a second account to see if that would work. In the event I disabled SSL on the first account and that solved the problem.
Then I removed the second account. I thought the warning about losing mailboxes would not apply because nothing had come in through this account for the short time it was enabled. How wrong I was: all the mail content (but not the headers) in my Inbox and Sent box disappeared.
I followed the Apple advice, which is to use mailbox>rebuild. I did this in both Inbox and Sent box - and hey presto, all the headers vanished too. So I had nothing but the last two days of email left. Fortunately, all my other mailboxes are OK.
I need to know:
Do the disappeared messages from my Inbox, and their attachments, all exist somewhere on my Mac even though I can't see them (I have searched the Library)?
Is there any utility out there that might help me to find them?
And what happens to attachments in Mail nowadays, when there seems to be no separate Attachments folder?

Answer 1

all the mail content (but not the headers) in my Inbox and Sent box disappeared.
Setting up the same account twice in Mail is probably what got you into trouble. I suspect Mail simply removed all mailboxes associated with that account without checking to see whether they belonged to the original or the dupe.
Do the disappeared messages from my Inbox, and their attachments, all exist somewhere on my Mac even though I can't see them (I have searched the Library)?
Very unlikely. Try looking in the ~/Library/Mail/ folder (where '~' means "your user folder). See if there are any mailboxes still there that might be appropriate, and try duplicating them to the desktop and then import them into a new mailbox. That's unlikely to work, but you never know.
Is there any utility out there that might help me to find them?
If they're really gone, no. If you have backups, you can restore them from the backup, of course. But without backups, the best you'll be able to do is try a data recovery tool, which is unlikely to give very good results in this case, but would be worth a try if there's no other option.
And what happens to attachments in Mail nowadays, when there seems to be no separate Attachments folder?
Attachments are stored with the message, just like they are sent across the internet as part of the message. They are not automatically decoded and saved as individual files somewhere. That happens when you either open them or tell Mail to save them somewhere.