There are libraries for matlab (and I think matplotlib too) that let you interpolate the ColorBrewer maps into gradients. Here's the matlab one: http://www.mathworks.com/matlabcentral/fileexchange/34087-cb...

Also for gradients, I wrote a pretty simple colormap editor here: http://colormap.org/. This maybe gives too much freedom, since it doesn't enforce any best practices as far as colorblindness is concerned. But if you make sure the brightness (the gray line) is monotonic, it's a step in the right direction.