Attached is a patch which makes some changes to each plugin's autogen.sh script (copies out the autofoo parts into a separate "bootstrap" script, whereby autogen.sh includes the bootstrap script, and calls configure), as well as includes a toplevel configure.in and Makefile.am to hook up all the plugins. The reasoning for this is that the toplevel autogen.sh only wants to call the bootstrapping part, but not configure of each plugin, or it'll increase the autogen.sh time substantially.
I've excluded some plugins because they either have no autogen.sh script, and/or don't have a working build system yet. But once it's all done, you can just update the list of working plugins in the toplevel autogen.sh, configure.in, and Makefile.am.
Pros: * No need to merge the po/ directory * Plugins can be distributed and built independently or together.
Cons: * No way to disable plugins yet, though that can be added using AC_ARG_WITH, AC_ARG_ENABLE, or something. * Long configure time, due to repeated checks from calling each plugin's configure script.