Ahem... No. Although I don't use custom papers enough when I'm using Painter IX.5, these are some of the textures I've scanned and made into papers to bring crunchy grain and roughness into my work (occasionally). In these cases I've scanned my old oil painting palettes which ended up fairly rough and interesting after cleaning/drying/painting/cleaning/drying/painting over a few years.
Also posted a, well, tacky and cheesy image I'd made using some textures and slowly building up the colours and turning down the 'grain' setting on the painter brush I was using (It took me ages to figure out how to use textures - the grain setting needed to be turned right down to less than 18% to really make any noticeable difference in the result).
You won't often see me use the technique so blatantly, but its another tool in the box of tricks, eh?