Those aren't standard sizes. How precise do you need the measurement to be? You can get 0.032" thick brass, but in fractional widths. If you're ok with 1/4" x 0.032" that's available. Similarly, the best I can find for 0.050" thick is 1" wide.
Most metal suppliers assume that the customer will machine things to their required dimensions, so there are only so many choices. What are you trying to make? It strikes me as being quite chunky for N.