If any Win32 folk are interested in testing, we may be able to get updated win32 libs more easily via the OpenSUSE build service. The dll for libcairomm from the service is only 155k by comparison. I'm not sure if the cross-compiled libs will introduce issues, but in my own testing for using the cairo dll from there a few months back, it seemed like it might be viable. Note: I would say to go whole hog and replace as much of the existing devlibs on your local system as possible.
http://download.opensuse.org/repositories/windows:/mingw:/win32/openSUSE_12....
A python script to assist with the process: https://github.com/mkbosmans/download-mingw-rpm
As an aside, if anyone does decide to try this, if you're really brave they also produce 64bit dlls which means with mingw64 you could possibly compile a 64bit Inkscape binary. http://download.opensuse.org/repositories/windows:/mingw:/win64/openSUSE_12....
Cheers, Josh