Hi,
I've been searching for the same thing, the only one I've found so far is from ERA.
COLD AIR BOX w/BACKFIRE PLATE: For Inglese Induction Weber Manifold - $800
Not sure, but it may only fit this manifold setup, also thought that the price was a little high but then I haven't seen anything else to compare.
Sorry, not much help....and I know the question has been asked before on the forum but hasn't sparked much of a response.
Cheers,