There are cats and cats. Last summer when we were beating against the wind my wife asked me: Where are they going? She was referring to a brand new Mooring 40ft cat. I had some difficulty into convincing her that they were doing the same as us, meaning tacking against the wind. The reason of her disbelieve was the very different angle: Maybe 27º to 40º?
We pass all afternoon tacking against the wind and when we were approaching the destination, I mean only two tacks to go, they passed by us, motoring directly against the wind
...and I guess they were doing that for a while.
There are faster cats and slow cats but I don't know why you think that the trimarans should not be considered. If I had the money I would prefer a trimaran. Look at this one:
Regarding Cats I agree with what you say, just adding that distinction between slow and fast Cats. I would also add this:
For the same size multihulls are more expensive than monohulls and less seaworthy. They have also more interior space.
Regarding seaworthiness I am not one of those that consider cats unsafe, what I mean is that a 40ft monohull, generally speaking, is an offshore boat while a 40ft cat is also but by a lesser margin. The Cats made for offshore work are considerable bigger than 40ft and that makes them even more expensive as an option as an offshore boat.
Trimarans have, regarding size, a better seaworthiness. I would fell more comfortable offshore on that 35ft Dragonfly than in any 40ft cat.
But one of these babies:
Is pretty much a perfect offshore cruiser. To be comparable in space and performance we would need a 80ft monohull and the prices should not be very different.