i had a plan that didn't materialize; not sure how well it would have worked -
take 2 five-gallon buckets. drill lots & lots of small (1/4") holes in the bottom of one of them. cut long strips of fabric (6 to 8' x 4"), stuff one through each hole, and tie a knot in the strip on the inside of the bucket so the strip can't pull out. gather the strips up in a bundle at the other end, tie them all together, and tie a weight onto them. suspend the bucket with the fabric streamers above the normal bucket, fill the top bucket with greywater, and hopefully as the water diffuses down through the streamers it evaporates before reaching the tied-together end of the streamers (which should hang inside the bottom bucket). the bottom bucket catches any drips, which can then be put back in the top bucket.
it'd probably require a bit of tweaking to make sure the water didn't drip through too slowly or too fast, but i think it'd work, and it'd take up a lot less room than an evaporation pond.