Suggestions for solar / LiPo powered 3.3v supply for Arduino
So to confirm - you want a LiPo charger + a buck-boost regulator to 3.3V (primarily cause you want to be power efficient).

So you have a ton of options. If you want to go with the Microchip battery charger that comes with the Sparkfun breakouts (https://www.sparkfun.com/products/10217) or Adafruit breakouts (), there are a ton of buck-boost regulators you can put in the next stage. I personally use the TPS63031DSKT in one of my designs, and I'm using the exact same schematic as in the first page of the datasheet (http://www.ti.com/lit/ds/symlink/tps63031.pdf). The efficiency curve is great for the Iout range you are expecting.

However, if you are starting from scratch, I'd look for a PMIC that combines the two like the LTC3558 from Linear (http://www.linear.com/product/LTC3558). That will really help cut down on board space, and cost. Really great chip - all its missing is a battery gauge. I know that MAXIM makes similar PMICs but I can't find it right now.