[@natekinkead Participant 5 years, 5 months ago]

I know this thread is super old, but I thought I would jump in here to let anybody (who stumble upon this thread) know that I developed a free plugin in the WordPress plugin directory that adds voting to bbPress. https://wordpress.org/plugins/bbp-voting/

Just like the OP found, there was nothing out there that offered this pretty common functionality to a bbPress forum, so I developed my own plugin to do it. I hope you like it!