I think you are on the right track. Very difficult to get a boat that performs well though. I would not be put off by 50' though. 60' would not be much different in handling 2 up.This is more than academic for me.
I am transitioning from a sail boat racer who likes to go cruising on vacation to a cruiser who will go sail boat racing for my vacations.
I am clear on one thing. I will always keep my race boat and my cruising boat entirely separate. The compromise doesn't work for me. When it comes to the racing, I understand my addiction. It is reasonably under control . Two identical boats, one in Europe and one in the USA, racing with and against life long friends.
The choice of cruising boat for the next chapter in my life is not under control at the moment.
Here are my criteria:
1. I want to be able to make fast passages. Even if it is a day sail, I like to get there in 4 hours rather than 6 hours. If I am running from the Galapagos to Marquesas, I want to make a fast passage. I have not defined the pace precisely yet. Should I be looking for 200+ nm days? Not sure yet. There is no overlap with the speeds I accomplish when racing. I want a fast ,comfortable passage not the fastest passage. Prompt not terrifying. I have plenty of opportunities to scare myself when racing in the vicinity of rescue.
2. The vessel should be a joy to sail. I love everything about sailing, the feel of the helm in my hand and the feel of the deck under my toes. It is the most relaxing feeling in the world and I want a boat that conveys that feeling. I know that there are some fast cruising mono hulls that convey that joy. I know that racing multihulls offer joy (because I have raced on them) I know that condomarans do not. I have not sailed on a performance cruising multihull.
3. I want to be safe and I want my family to be safe. I know two things. One, I intend to avoid sailing in 40+ knots of breeze.....Two, If you sail for long enough you will get caught by 40+ knots of breeze.
4. (a) The saloon and daily living space cannot be the cave. If you are sailing in beautiful parts of the world , part of the experience is being surrounded by the beauty when you are sitting in the saloon with the family, not just when you are at the helm
(b) I can sleep in a cave (aka hull) just fine. (As long as the motion is joyful).
Steve and Liz Dashwood have done this with their monohulls so have Boreal and some others. The performance cruising cats have done this....but I have never sailed a performance cruising cat.
5. The boat has to be really well set up for short-handed sailing. Chris White made a really wise comment on the video. Most cruising boats are sailed by couples, which means they are sailed single-handed because someone is sleeping.
My accommodation requirements are less demanding than most. We have one son at college. I like to think he will join us from time to time and I hope he will bring his significant other. It is too far out to contemplate his children. We will have a couple of friends or family from time to time because so many of our friends and all my family are sailors. But the length of the boat is determined by my sailing requirements not the number of berths.
6. Length. I differ from the post about volume. Length affects sailing. I havent drawn a line in the sand but somewhere around 50+/- gives me performance, safety, comfort and single handed maneuverability
So I am somewhat flailing. One Friday I am looking at higher speed expedition yachts and the next reading up on performance cruising multi-hulls. The good news is that list is gradually getting shorter. The bad news is that it is gradually getting more expensive.
I am adding Chris White to the list.
Get any boat weighed before you buy it. Catamaran claims of light weight are often greatly exaggerated.
From my perspective sailing fast in light air is the real holly grail of a cruising multi. I am really not interested in sailing around fast in 30kn of wind.
One boat in Aus which may work is Windswept a southern ocean 56. Build a couple of queen berths outside the main cabin along the back beam, a good cockpit cover and you would have a very comfortable very fast cruiser.