I have a new site covering the phonology and tones of Mandarin dialects (and all the othes). I'm still adding data, but you can currently view tone data for more than 100 dialects. In the near future there will be several hundred Mandarin dialects entered.
http://www.glossika.com/en/dict/lang.htm
The Mandarin tone data is here:
http://www.glossika.com/en/dict/tones/guanhua.htm
And a list of the dialects here:
http://www.glossika.com/en/dict/dialectm.htm
James Campbell