Bolt Thrower and Chasm are obvious contenders, both mentioned in this light very often on this board.
But I actually agree with Revbiz above, even though technically they only have 3 albums. III was my favorite for a while and I think we could easily consider Return To The Rectory a fourth album.
EDIT: I don't know Type O Negative's disco well enough to comment on that and I admit I only ever listened to the early stuff that reminded me of Carnivore.
I think we can safely count Harbinger of Metal a full length as well, being that it's over 70 minutes long.