I am using two FlightPower 800-mAh 2s Lipo's with two [link=http://www.tech-aero.net/plr5-i]Tech-Aero reg/switches[/link], plugged into separate slots in the RX, which provides battery redundancy, and the IBE provides ignition power from the Rx. Therefore, you get igintion and also Rx redundancy with 2 batteries.

All these items together weigh 5.7 oz, plus a little more for mounting, which I haven't exactly figured out yet. The Lipo's come with JST leads which I will have to change to Futaba.

All in all, not bad at all for a 1600-mAh redundant power supply that includes ignition power!

Also keep in mind that this is somewhat offset by the fact that the fuel tank is 12 oz versus 20-24 oz for glow.