Tom (2 Door) made that bent seat post out of a solid piece. Thing is awesome! Really, really makes for a better ride. I can not recommend them enough. The only other place I know for sure that has them is Spooky Tooth Cycles - Motorized Bicycles: Gas Powered and Electric Bikes - Seat Posts
Truly, well worth the $. I wan't to make one with some sort of spring.
The acid wash idea sounds cool Trey. Have any pics of a bike after doing that?