Thought I would try to get WLS 8.1 running on my iBook this afternoon. I seemed to remember hearing that it was possible, so I thought I would give it a go.
Turns out it is very simple. Thanks to the instructions posted here, it took me longer to download the WLS distribution, than it did to get it up and running.
The whole thing hinges around downloading a generic version of WLS, and running some custom install scripts.
Screenshots of the WLS console can be found here (running in IE, because for some reason Safari doesn't like it), and below is a screenshot of WLS running in a terminal window.