Black Lagoon and Yotsuba&.
The first is basically a dark and edgy Micheal Bay film with good choreography and three-dimensional characters. It could easily work as a summer blockbuster without fans of the original.
The second could be hit or miss, since cartoony characters in a realistic setting is part of the series' charm. But "Yotsuba & Revenge" as a short film would be one of the greatest things ever.