Over the last couple of days I've been experimenting with getting Workout to work on Windows. With the help of some tricks borrowed from the Marble and Quassel teams (and even, *blush*, lifting a few lines of code from the Quassel sources), I got it to work.
It's not 100% done (configuration does not yet work and neither does hardware discovery, which will require some extra effort on Windows due to the absence of Solid), but it's running and mostly working:
Note that this is a Qt-only version. I did try building it with the KDE-on-Windows project and even had an app that started, but in the end decided to make a "pure" Qt version, mainly for packaging and distribution reasons.
Of course a KDE-on-Windows-version is still possible to make: The KDE version (be it on Linux or somewhere else) is not being negatively affected by this at all.