@SupraSPL
What's your take on how much shape influences surface area requirements?
On the Cutter site, they claim that mechatronix lsb-9950 can handle 30w of heat but with a surface area of only 1392cm^2, that hardly seems like enough surface area to effectively cool 30w passively (As greengenes pointed out).
But my understanding is that your passive figure (120cm^2/w ?) is derived from the heatsinkUSA heatsinks not something shaped like the mechatronix.
Being able to passively cool a 35w or even a 50w cob for $12 would be a gamechanger!