The answer to this depends a lot on the size of plank you are after. If you are talking about a 4mm wide, 0.5mm thick "plank" then I would forget DIY and buy from one of the major suppliers (Cornwall Model Boats for one) - or simply buy some veneer and slice it up with a straight edge and sharp blade. If you are after something more substantial, say 10mm wide and 2 or 3mm thick, and you have some respectable cutting machines, then it is quite possible to do it yourself. If you look at the log of my Solent steam launch build (link in my signature below) and go to Reply #4, that is how I did it.
Greg