This is really great Kathy!
I'm not familiar with a number of these sites.
I'm going through my list to see if there are any that aren't in your post.... Only one, - I was searching for lemon grass seeds at one point.
On the Seeds of Diversity web site there's a listing of vegetable and fruit seeds sold in Canada in 2008 and who sold them. Some of the companies probably don't exist anymore as there are broken links, but it's a great place to start tracking down specific seeds (and probably come up with some more companies).
I've been watching for this one to come back: