I think Gamestop's US Xbox pre-order Blood Echelon armour set and claymore was an exclusive. A different English release had Defenders of Aleroth Armour, and at least some Italian and Spanish versions had downloadable items. There are a couple
contests in North America that have bonus items as one of the prizes.
With the framework in place for downloadable equipment, it would not surprise me if there were other releases at some point. There has been nothing said by Larian about any plans for downloadable content, though.