Try making your own from the off cuts. They used to call them Trennals, or tree-nails.
You need a piece of steel plate about 5 mm thick. Drill a hole in it with a SHARP drill the same size as the dowel needs to be, or better still a TINY fraction larger. You need to preserve a sharp edge on the entrance to the hole. If you can taper it very slightly, 1 or 2 degress all the better, but it's not essential.
Select some straight grained offcuts about 6 inches long, cut or split them square a little larger than the hole, round the end and shave the edges. Then tap them through the hole to make your own dowels that match your work exactly.
An old dodge, hope it helps