This IS the Avid L2: [Avid-L2] Blurrier blur out to edges?

Another editor asked me some questions about placing a blur around the
edges of a shot.

We looked at a blur matted over the original shot but the consistency of
the blur didn't achieve what he was looking for. He wanted something
that gets more blurry out to the edges.

I imagine one could do it with a series of mattes each adding an
increasing amount of blur out to the edge but is there some plug-in that
just does it within Avid or BCC?

TIA,

D.