If your not too worried about weaight check out the Xantrex XPower 400R. http://www.xantrex.com/web/id/177/p/1/pt/30/product.asp
I have one of these and use it frequently with both my 2m/70cm rig and my K2 qrp. It has a Built-in 400 watt inverter and a Sealed, non-spillable 20 amp-hour AGM battery. I find it to be quite handy even if it is a bit heavy. I wouldn't want to take it backpacking but for car camping and genral portable use it is great.