Lyman, the point is, if the map is not NATIVE 300 dpi, it can be hard to read type, or other details. That is why we have the file requirements: 8½ x 11 inches; 300 dpi NATIVE resolution; no screen backgrounds; less than 500 kb file size. Color is only accepted if the file size can be less than 500 kb as a 300 dpi png.
Your image is not 300 dpi, and would not fit the spec of NATIVE, if it was simply converted to a 300 dpi file. A low-res television image looks like garbage on a hi-def television. Why? It still doesn't have enough ORIGINAL detail to look good with twice, or 4 times, or whatever the count, pixels.
Until you can provide a png that is 8½ x 11, 300 dpi NATIVE resolution, and 500 kb or smaller, there is no discussion. Only when we achieve the current standard will it be time to discuss increasing file size.
There is a reason we have the 300 dpi native resolution standard, and it is not being met my many people who wish to submit digitally. We won't loosen standards just because it is not simple to accomplish. You talk about quality to our clients; 300 dpi is one of those quality standards.