cyclegadget:
Have you tested the step-up regulator with much of a load? I ask because I would like to run about 140ma of blinking LEDs of a minimal Arduino using a 3.7 lipo battery. It would be awesome if the regulator could truly supply 1A at 5V.
I wouldn't bother generating 5V and then wasting 1.5V or more in the series resistor, instead I would drive each LED or bank of LEDs from the 3.7V supply using a simple unregulated boost converter. To make the converter, you can adapt the joule thief circuit (but then you need to wind a transformer), or use a PWM pin driving a transistor and inductor, or use one of the many ICs that are available for this application.