Now that OSL is open source (congrats!), I recommend using the following guide on crediting patches from non-core developers in log messages:

https://svn.apache.org/repos/asf/subversion/trunk/www/hacking.html#crediting

You can then use the Contribulyzer to analyze commits to see who you would like to promote to full committers:

http://www.red-bean.com/svnproject/contribulyzer/

See this chapter "Teams and Tools" from the "Beautiful Teams: Inspiring and Cautionary Tales from Veteran Team Leaders" book by Karl Fogel, one of the Subversion founders on the tool and the issues it sovles:

http://www.red-bean.com/kfogel/beautiful-teams/bt-chapter-21.html

Regards,
Blair