I tend to issue ctrl+home to go to the top of the page. Then I issue X to find the first email on the screen if there is one. I next issue a comma to drop out of the list. I then issue shift+X to find the previous email. This has worked well for me if I want to find the last email on the screen.
You could just go to the bottom of the page and then issue shift+x but this will find a check box below the table of emails first if there is any.
