The October 2012 issue of Mind (posted today here) has an extended discussion section where mathematical fictionalists of various stripes respond to Colyvan's earlier article "There is No Easy Road to Nominalism". The discussion concludes with a detailed reply by Colyvan. While I am a fan of neither Colyvan's explanatory indispensability argument nor its fictionalist critics, I look forward to reading this discussion and engaging with it soon!
Jody Azzouni Taking the Easy Road Out of Dodge Mind (2012) 121(484): 951-965
Otávio Bueno An Easy Road to Nominalism Mind (2012) 121(484): 967-982
Mary Leng Taking it Easy: A Response to Colyvan Mind (2012) 121(484): 983-995
David Liggins Weaseling and the Content of Science Mind (2012) 121(484): 997-1005
Stephen Yablo Explanation, Extrapolation, and Existence Mind (2012) 121(484): 1007-1029
Mark Colyvan Road Work Ahead: Heavy Machinery on the Easy Road Mind (2012) 121(484): 1031-1046