I had some spare time today, so I dissected two of the bright sticks to see what they're made of. Feast your eyes on this.
Ten watt (60 watt eq) have 6 SMD chips in them on a flat aluminum plate.
15 watt(100 watt eq) have like 2 dozen SMD chips in them! Plate is only a little bit larger.
Lo and behold, no unsightly massive heat sink to be found... unless you want to count the little plastic shell. It's lined in the inside with some aluminum foil that contacts the circumference of the plate, so it Methinksould make awesome little fog lights.