http://www.cruz.senate.gov/files/documents/Briefs/20150409_MarriageAmicusBrief.pdf
Last couple of pages lists the signers.
Thanks much.
I also just found this. All the briefs for and against.
http://www.americanbar.org/publications/preview_home/14-556-14-562-14-571-14-574.html?cq_ck=1425077268167