1) Picked up a small, cigarette-pack sized 5-port switch from Fry's for $20. The power supply was rated at 5V, 1A output.
2) Also from Fry's, I picked up this mini USB charger for $7. It is rated at 5V, 1A output. Perfect.
3) Converted from cigarette socket to wire harness for permanent wiring in plane.
- Disassembled the charger.
- Discarded the springs and clips that provide contact points for the cig lighter.
- Soldered wires to the 12V lead and to the top of the USB cage.
- Put everything back together.
4) Spliced a USB cable with the power cord for the switch. Done. Works great. 12v in--->5.15V out. Even has a red LED to indicate it's hot. I'm running my home network off the 5-port switch for a few days using this assembly hooked up to a 12v power supply.