Anthony, the one at the end is the olive one. I was darker than the green colours they have had in the past and it looked good in both. I don't know if you've seen this page.
K-30?PENTAX RICOH IMAGING
The colours in real life were pretty close to how that page looks on my monitor. The only difference is the silver one, which is more like like grey. Actually the matte grey one is pretty cool. It would look good with an F series lens on it. The good news is the three standard colours are all very nice.
As for cheap plastic, I think that's probably right, I think the crystal ones look like they'd wear better. But the stock black model is made out of the same stuff as the K20D. It has that cracked finish and feels more grippy and rugged. If it were me, I7d get the yellow, but that's partly my regret from getting the boring black version of the K-01.