Black or white keys of jazz chords?
Python3, 293 242 bytes
This is my first CodeGolf. I am curious to see how others do this.
def f(s):
 for j in 4,3,2,1:
  try:return ''.join(['-^--^-^--^-^'[('A BC D EF G'.index(s[0])-('b'==s[1])+('#'in s)+i)%12]for i in(0,)+{'7':(4,7,10),'M7':(4,7,11),'m7':(3,7,10),'dim7':(3,6,9),'m7b5':(3,6,10),'-M7':(3,7,11)}[s[-j:]]])
  except:pass

Edit on 01.06.15
Thanks to the commenters, we found some tricks to shorten the code. I also discovered that changing to a function is slightly shorter. Old code: http://ideone.com/j5gmV2. P.S. I am just copying the code into triple quotes in Python and calling len to get the number of bytes.
Note:
I am assuming that Bb-M7 is Bb Major/Minor, i.e. that there is no delimiter between the note and the chord type, as described in the OP's second paragraph. Thus Bb-M7 gives ^^--. If Bb-M7 means Major, then what is Bb Major/Minor? Should it be Bb--M7?