Not yet, but I believe nohwnd is looking into this for an update in the near future. I'm not sure yet what the syntax will be.
The current logic of throwing an exception if no script block is present is probably a good thing to keep, just in case people try to put the open brace on the next line by mistake. It'll probably look something like this:
It "is a pending test" -Pending
Where the Pending switch would exist in a different parameter set.