well what are you trying to do exactly? just simply have a long lasting flight where you can lay back and relax all day? or something to do cammera work? or carry a 1 pound bomb at 5mph at a target 20 miles away for a couple hours? it would help us out a little bit if your questions and goals were not so vague. we need more details.

if your interested in electric, im currently building a newer version of the Bird of Time. fiberglass fuse, D-wing (super strong yet very light), and a very VERY powerful E-Flight Power 25 motor. its 550 watts, about 40 amps, 870kv, spinning a 14X9 folding prop. it will be using my Air Thunder 2200 3S lipo's (when ever they arrive). but with a 3 meter wingspan, you could take this thing pretty high and still see it.

you can buy this kit at the Espirit Models website, they are great people to deal with.