the 5 inch e-ink display costs about $45-$50 dollars in volume from PVI. Sure a $50 dollar device would be nice. but you just cant make it that cheap. The only way to get a reader that cheap (for the next year at least) would be to subsidize it like a phone - offer it with the purchase of a book club subscription that you are locked into for 2years....
thats my idea btw- consider it copyrighted and trademarked by me today 2010