I found this one on another boating site. My apologies if it has been posted here before; http://empdigital.net/studiofranco/home.html
Looks like a sweet ride. I say they put a couple of MTU 16v2000CR just for fun. With that, can anyone come up with an estimated cruising speed?
"The SC117 will be propelled be either surface drives or water jets. The yacht's optimum cruising speeds will be in between 40 and 50 knots and exceed 60 knots." If you click on the 'SC117' button it will give you some speeds. They say a max of 65kn which is what, 75mph? However they don't say what engines they will use. I suspect a big diesel power package as you said. 2000hp diesels with probably make 60kn with jet drives and 65 with Arnesons or BPMs. They don't say if hydrofoils will be used in the tunnel but that might be advisable on such a big cat. The Prout 64 catamaran has them as an option but has much less performance without them.
The bad thing is there's no contact information on the site, so even if you wanted to buy one you can't.