So with much a-fiddling, I discovered that you can create floating workspaces with the default keybinding "F9" - At the prompt, "Go to or create workspace: " enter WFloatWS:<workspace name> where <workspace name> can be anything. Hitting F2 starts up my friend, xterm, on this new floating workspace.

I haven't yet figured out how to create empty WFloatFrames, but I'm working on it. It seems that if the parent frame has only one child you can't cfocus the parent until the child is dead.

That is:

WIonWS
  |
  +---> WIonFrame
    |
    +----> WFloatWS

You can't give focus to the WIonFrame until WFloatWS either is destroyed or moved outside of the frame. I'm sure there's a way around this.