WME 1.7 beta 1 is pending and there's no release date, however a new feature has been announced. It's stencil shadows. The hidden scene geometry will get an overhaul, and a more detailed mesh will have to be included for shadow receiving sections. On the WME forum, someone suggested a "reflection" flag for shiny floors(for example) and Mneumonic mentioned that that will be easier to implement with the new mesh data and will probably be the next major feature after stencils are perfected.

http://www.dead-code.org/blog/?p=6