You'll need something that has low Q (overdamped) and rolls off gently in the bass so that you don't get too much boosted response from the corner placement - something like a Vandersteen sub or REL perhaps?
Subs for coners or built-in sub inside speakers
I'm unfortunatley limited for space - I'm looking for sub that is best suited for corners or should I look deeply into speakers with built in subs like Definitive Tech BP series - I don't know of any other speakers out there with the same concept as DT - your suggestions/recommendations will be greatly appreciated....