I'll show you a workaround in the meantime.
Similar to what you requested can be accomplished by choosing "Horizontal A" colormap rendering and a tiny bit of tweaking (example for Python interpreter):
1. We put the colors from your linked page to a list, and then pad those colors with "00":
cl = ["669900", "006699", "0066FF", "6600FF", "660099", "CC0066", "FF0000", "FF6600", "FF9900", "FFCC00", "FFFF00", "99CC33"]
cl = [i + "00" for i in cl]
2. Let's suppose our musical spectrum displays 8 octaves (starting from C for simplicity), thus:
number_of_octaves = 8
cl = ''.join(number_of_octaves * cl)
which we'll append as bytes to a "header":
header = '001E099F08928D40818A1619B19AA41A2C000000E86700001878' + \
'%02X' % (number_of_octaves * 12) + \
'03C4000D00F4013200B8011900FFFF0300C0C0C000FFFFFF002E354300F8F8F800B0B0B000'
Header contains some settings about musical spectrum configuration and important in this case - number of colors we want to introduce - 8 * 12 = 96 or in hex = 60.
3. Than we pack everything to binary file:
with open("colorpiano_8oct.cfg", "wb") as f:
for i in range(0, len(header + cl), 2):
f.write(chr(int((header + cl)[i:i+2], 16)))
Result:
So this is very simple walk-through how to get there from Python interpreter.
Cheers