Which e-readers are capable of sending books by e-mail?

Hello, I have a PW3 and I'm really happy with Send to Kindle feature.

On Calibre I defined my Kindle device's email and can send books to my Kindle directly. Also I use a website to download books and they have this feature implemented, so when I select a book I can click "Send-to-Kindle" button and it directly appears on my Kindle.

So, now I am looking for new e-reader devices for my sister and my mom. And I want them to be able to use that wonderful function to send books to their e-readers :)

Is there a list of e-reader devices which support "send-by-email"?