I have set up automated builds for mingw4, msvc2008 and mingw-w64. These build all packages from this list: emerge/server/serverconfig/packagelist-win32libs.txt The Results are displayed on this dashboard.
If you want to add a package, add the package to the above list in svn and wait 1-2 hours until the server has started to build the package (it checks for new packages every hour on the half hour). If you want to update an existing package, change the package in win32libs-sources category in emerge, and rename the package file! The server only builds the default target, so if you change the target, you can get a new package (but only if you have also renamed the .py file).
After your packages have successfully built, please also update the win32libs-bin section with the new package/updated package. For this, run
%KDEROOT%\emerge\bin\win32libs-updater.py %KDEROOT%\emerge\server\serverconfig\packagelist-win32libs.txt. It will generate adapted .py files for you which will give you the correct results based on the win32libs-sources section. Then commit the changed/newly added files (NOTE: adding doesn't work yet).
In the win32libs-sources section, please specify exactly which dependencies you have, splitted between self.dependencies (needed both at runtime and at buildtime), self.buildDependencies (only needed at buildtime) and self.runtimeDependencies (needed only at runtime). This is needed for the win32libsupdater.py script to work correctly. Dependencies on other win32libs libraries should always be the binary part of them! Please think of that. If you have any questions, do not hesitate asking SaroEngels.