Here's a real good link I found a few years back.
It's a link to a site called the Mitchell Reel Museum. I don't look at it every day but, it's always informative because it's constantly evolving and the information is often updated. For instance, I used to say I had a Mitchell from 1949--turns out it's from '51. It still has a little history!
Check it out now and then visit again in three or four months. If nothing else, you may like the pictures!