I got it, luckily, at home depot... they have a huge and messed up molding area... I went looking late last year for somthing that would take the curve and found wood too stiff. Not sure what type of plastic it is made from, but it is quite bendy.... getting it to stay bent is another story... it will, but it takes persuasion. It is about 4 bucks for 8 feet of it.
It is a light oak color, but I painted it... not sure if it comes in darker shades or not, as I was looking for shape and bendability... color didn't matter.
I even thought of just cutting a 1 inch strip of 1/8th ply to use, but this has a nicer shape.