Good 8" subwoofers off the top of my head that will handle 1k+
Sundown SA8 (rated at 600 IIRC, but I've seen them do 1k+ in the right box)
Atomic AP-8 (SPL version is rated at 1500 RMS w/ 3" DVC)
Massive Audio Hippo 8 (due out in January just before CES, this is my future subwoofer)
Digital...