Hi
sources for new project plugin are here:
git clone git://repo.or.cz/geanyprj.git
or
git clone http://repo.or.cz/r/geanyprj.git
Plugin is in early development stage, but it is already can be used to provide custom build dir.
To geany devs: Please, apply attached patch, it adds few utils functions needed by this plugin to api.
Best regards, Yura Siamashka