We have learned from experience that it is very hard to find decent accounting company as skilled with GnuCash as they are skilled with proprietary accounting software.
In 2012 we did survey among ~15 local accounting companies in South Sydney in attempt to find whether any of them can work with GnuCash and we were lucky to find the only business sufficiently competent and willing to work with GnuCash: Award accounting.
Award Accounting is a great team lead by Amanda Ward, the extraordinary professional director and CPA.
Libre Solutions Pty Ltd wholeheartedly recommends Award Accounting as GnuCash friendly CPA.