Turns out it was in the the mailbox today. I haven't tried it in bright sun so don't know if it helps, but it might. It definitely helps with manual focusing, no question. That is true both with and without focus assist. It magnifies the LCD so much that it's almost too much -- you really see clearly that you're looking at an electronic viewfinder as opposed to optical. But I suspect I will be using it a lot.
You could search on Extend a View and Hoodman Loupe to see if they've been mentioned here before. Good luck!