Low Profile Power Dissipation
voltage regulators come in two types, linear and switch mode.  linear regulators work well when the voltage in is near the voltage out, but rather poorly if the voltage in is higher than the voltage out.  What you need is a switch mode regulator.  A few minutes on digikey suggests that a LM2574 will do the job.  The down side of using such a regulator is that they require a couple of additional discrete components (a handfull of capacitors, a schottky diode and an inductor, in the case of the lm2574) to work, but they dissipate basically no heat.