Yeah, I would be really tempted to snatch up that Duke not only for the aluminum neck, but also because that color in a lefty headless is VERY rare, except that I already have a headless 4 (and a 5, and a 6
)If that Kramer isn't your thing, then I would highly recommend the Hohner B2A and B2AV (Hohner also makes a B2B with PJ pickups, but I don't think it's available in lefty). They are solid-built (all maple, neck thorugh) and fantastic playing instruments for the money, and sound pretty good. The B2A has two humbuckers, while the V has jazz pickups (I prefer the jazz pickups myself). I like these better than the Steinberger Spirits because the Hohners have an active preamp, although the Hohners do cost more. They aren't too easy to come by, though. Here is a V for sale, although I think it's a bit overpriced:
http://www.wholenote.com/item--HS.B2AVLH-WS
The walnut satin finish is somewhat darker than what is shown in that picture. It also comes in a yellow/red burst, which I definitely do not like as much as the walnut satin.
The description of that Kramer says it's a short scale bass. The Hohners are full-scale 34".
Also, the Kramer does not require the double-ball strings. The Hohners do, which I don't mind because the double-ball bridge and headpiece that the Hohners use make the bass a little more compact than the Duke. The Hohners don't have that extra body mass behind the bridge to accommodate the standard tuners. Plus, you can always get a string adapter for the Hohners.
(except he had it strung upside down so he could play a sound sample).