Massive Audio DMX
Kove Armageddon
4hp's (whichever flavor you find, such as eclipse, cactus, TC sounds, T3, blah blah)
DD9500 series and 9917's
Emphaser
FI BTL
RE MT (extremely overpriced, see FI for real price on a similar sub)
TREO CSX
Audioque HD3
old Adire Brahma's
American Bass VFL
MTX RFL
Team RF
Kicker Solo series
alternatives for SPL subs that dont cost an arm and a leg :
Massive CW
Stereo Integrity Magnum
Alpine R
Kicker L7
RF T2
Orion H2
thats just some off the top of my head //content.invisioncic.com/y282845/emoticons/fro.gif.c695f1f814b01c4ad99fe7f8cccadd29.gif