1) A metal hull. If we really want to sail the Northwest Passage, we want a metal hull. Aluminum if we can get it.
2) An insulated hull.
3) Total length 39-42 feet. A little bigger if we had to.
4) Three sleeping cabins. One for us, one for the boys, and one for the survival suits/cockpit cushions/bikes/sails/deck awnings and everything else. Or alternately, two cabins and some very serious additional storage space.
5) A cutter rig. Or a sloop that we can convert to a cutter. Or a ketch, if we had to.
6) A skeg-hung rudder. Or even (god forbid) a keel-hung rudder. But not a spade rudder.
7) A well-maintained boat, with good sails and standing and running rigging.
8) A u-shaped galley.
9) Big water tanks.
10) A hard dodger (optional!).
11) A specific set of bells and whistles: windvane, radar, a good autopilot, an over-sized windlass, over-sized anchors and chain, solar panels, life raft, folding propellor, wind generator, ham/SSB radio, steps on the mast, cruising spinnaker. As many of these as possible.
12) 195 cm of headroom.
13) In our budget!
It doesn't seem like an unreasonable list. But though we've seen many boats with eight or nine of these items, we've never seen one with ten or more.
Some serious compromises seem inevitable.