rapala makes tail dancers in the "deep" model that go 15, 20, and 30 ft down. the 30 footers really pull something fierce, though. i dont fish any deeper than that because chances are you are killing whatever you catch from down there being that its being pulled up through quite the pressure difference as well as a significant temperature difference.

personally, im not a big fan of pulling sinkers. they dampen my feel of the lures action (less able to tell if its fouled) as well as when you get the fish close you have a big hunk of lead swinging around your face while you are worried about landing a thrashing fish.

deepest i fish on a regular basis is with a 20 ft tail dancer or a deep husky jerk 12, which swims around 25ft deep.

MT is more versed in the sinker world so if you plan to use one, follow his instructions  ;)