Mail crashing during send

Question

After searching the forums I've seen some posts that are similar to my problem, but none that are close enough to help.
When I open mail things appear to work fine, but when I compose a message (via send or reply) mail hangs for a few seconds, I get the spinning wheel, then it crashes. I've tried sending a report in to apple, but the report window is extremely slow; so much so that it's not practical to view the stack or send the report.
I do have a lot of accounts, most of them imap, but things were working until a restart. My mail box is quite large (100,000s of messages) but it seems to read them fine and I'd prefer not to delete my mail.
This happened some time ago, and I fixed it by restoring all of my Library/Application Support/Preferences files from a few days prior. This time I tried just getting the Preferences/com...mail.plist file (I can't recall the full name) and that didn't work. Now I'm attempting to restore all the preferences again, hopefully that will work but it's a long process so I'm curious if anyone has a better solution.
Cheers,
--alex
Dual G5   Mac OS X (10.4.5)  

Answer 1

Update.
This time a preferences restore didn't help, so I cannot send email at this time. Well I can, but I need to use the web interfaces to my various accounts. So, any ideas would be greatly appreciated .
I'll play around for a few days, if I don't find anything, and no-one on the list has any solutions, then I guess it's a wipe and restore -- which would be a pain in the you-know-what.
Cheers,
--alex