Couple more items of possible interest. On sale for $0.99US right now are select Brian Azzarello issues, including his "Broken City" arc and also the Flashpoint tie-in Batman: Knight of Vengeance. Comixology also recently added "Dark Knight, Dark City," considered by many to be one of the greatest Riddler tales ever, to their 100-page Spectaculars section.
The Azzaralleo sale has no announced end date, but I wouldn't expect it to go on past Wednesday.
Peter Milligan's "Dark Knight, Dark City" is $4.99US, the regular price. It also includes Detective Comics #633, also written by Milligan.
EDIT: The Brian Azzaralleo sale has ended.
On June 27th, Comixology added the Elseworlds title "Gotham Noir" to their 100-Page Spectaculars collection. It's Batman re-imagined as a hard-boiled private eye mystery.