Norm has an Idea and maybe you could start a trend
Build a few smaller gennies that will run the light strings, decorate trees with lights, then instead of the angel on top put the small genny
Just consider it part of the decorations and put it away at end of season like everything else if you want.
Build some yard stuff yourself? You can get that colored film for theater lights in more colors than you'll know what to do with. Make a box with reflective backing and cover front with plywood. Paint up a really nice design on the front then drill lots of holes around detail lines. Cover holes from inside with little pieces of the color film and light from inside with bright CFL.
You could buy a few hundred LEDS of various colors, make yard figures, drill holes, poke in LEDS and wire it up. Depending how many Leds you actually use it should run all season on one small battery on one charge perhaps. You'd have nice painted shaped figures durring the day and lights at night.
Same basic idea but maybe cheaper and easier than LED, buy allot of those plastic colored lightbrite pegs and poke into holes, light from behind with bright CFL. This would use more power than leds also I think though.
Along the same idea, take used beer/soda cans and make ornaments with the shiney insides, holes and leds and a few Nicad batteries for lighted ornaments around the yard.
Turn them on/off with a light sensor. I think I have a mofset and sensor for my 12V led string. Something Ghurd gave me early this year, works great only 2 parts, plus the battery and leds.