You can now pre-order the Spartacus Vengeance DVD & Blu-Ray sets. Both sets are due for release in September 2012 (according to Steven DeKnight)
DVD - Pre-Order Now $44.99
Blu-Ray - Pre-Order Now $44.99
Includes never-before-seen bonus features including featurettes, extended scenes and content too risqué for cable television.
No other information about extras on the Blu-Ray edition yet.