I’ve been keeping an eye on struts-wml. I wanted to use it on a project, but it was a little too alpha for me at the time. I wasn’t able to easily use the version of Struts that the release was mapped to. I gave up after a little .jar hell.
It is now sync’d with Struts 1.1b3, which might make it more usable for some. I’ll do my best to take a look at it in the near future.