GnuCash can be built to run more or less natively on OSX -- meaning without X11. Better yet, the build is almost automatic.
Please see http://wiki.gnucash.org/wiki/MacOSX/Quartz for instructions.
fellen/gnucash-on-osx
Gtk-OSX moduleset, gtk-mac-bundler bundles, and ancillary files for creating GnuCash OSX Application Bundle.
Shell