Of course, if you're running off a battery it's DC to start with, so you're avoiding using the inverter.
If houses started coming with standardized low-voltage DC alongside the regular 110 AC, manufacturers could perhaps start selling CFLs and LEDs without builtin transformers. Although I'm not what voltage they actually run on internally.
CFLs require a switching power supply because they operate at far higher voltages than line voltage. LEDs require some sort of current regulator, and a switching power supply is far more efficient than a series resistor. So, you don't gain anything for them by using a different voltage.
If houses started coming with standardized low-voltage DC alongside the regular 110 AC, manufacturers could perhaps start selling CFLs and LEDs without builtin transformers. Although I'm not what voltage they actually run on internally.