Besides TCM (Movies Unlimited), you should definitely check out Kino, The Criterion Collection, and Grapevine.
I've made purchases from all of them, but probably my favorite is Grapevine because they sell some rarities found nowhere else.
Here's the Valentino page, for example: http://grapevinevide..._valentino.html
Are there any listed there you don't have, or would be interested in?
Thank you thank you for those sites! That's great! I have really been wanting to find some good places to buy silent films, I'm so glad you shared these sites with me!