Martels Hammer said:
At the moment, this is just a project idea, but you bring up a good question I had not considered. What is the difference between using wood versus some of the plastic things I see offered online?
There are several different materials you can use. Not sure what your proximity to a good supplier is?
Pine...cheap, easy to cut, shape, stains okay, paints well.
Poplar...cheap, easy to cut, shape, wouldn't stain unless you are really good, paints well, knot free.
Red oak, white oak, cherry, walnut...$$$, only for staining.
MDF...cheap, comes in 16' lengths, pre primed, paints well, straight.
Plastic, hard foam...just no.
I used to hate MDF (medium density fiberboard, basically hard brown paper), but after doing a few projects like box beam ceilings where I did hundreds of linear feet of crown per project, I came around. It was cheap ($1 per foot), 16' lengths, straight, doesn't expand and contract much at all, pre primed, yes, when nailing, it 'mushrooms' a bit, but a bit of filling and sanding and the final product is great.
Buck C asked a lot of good questions. Follow that advice so you get what you want and can compare 'apples to apples' if you get multiple bids.