Ridley have released a clip-on aerobar which works with the integrated "cockpit" on bikes like the Kanzo Fast, Noah Fast, &c. (Maybe with some of their other brands too, like Merckx?)
They seem to have released it quietly; I didn't know about it until researching how to fabricate one for myself because there was nothing in the usual online stores. But if you contact your local Ridley dealer and ask for part HBMAER4ZA002, they should be able to sell it to you (approx €200).
by Useless_or_inept