Previously we had XtraBackup Windows binaries for 1.0 and 1.2 releases, and they were based on Cygwin compilation of MySQL.
After MySQL 5.5 moved to CMake, and cygwin compilation is not supported anymore, it took some efforts for us to come up with native Windows builds, but they are there already. We consider them “alpha” quality, as there some know limitations,
but you should be able to make backup and restore from it. If you are interested in Windows backup I encourage you to give it a try and report your experience. Binaries are available there http://www.percona.com/downloads/XtraBackup/XtraBackup-1.6/Windows-alpha/