I've lived on a Paceship PY 26 (fin keel/4.5 draft) for almost 2 years now. It's fine for 1 person, but a couple would be cramped.
The Paceship Website Homepage
has all the specs
The Centerboard model is probably better for trailering, mine needs a tractor trailer.
-6 ft. headroom
PY 26 has 6'1" except at door headers, cabin area is roughly 7x7.5'
-26 or 27 ft. (as far as I know, the max. length that still qualifies as trailerable)
Trailerable = gross combined weight, pickups are limited to 2-3000 lbs. gross combined weight, a tractor/lg. car carrier type truck would be needed to stay legal.
26' 6" x 9.5' beam (needs wide load signs) and 6400 lbs. empty, I'm around 7200+ lbs. now.
-outboard engine (avoid hassles of inboard)
I have the outboard option and it gave me room for a 45 gal. fresh water holding tank and other misc. storage where the inboard would have been. I'm currently moving my 3 batteries up front behind the head holding tank (under V-Berth) to help balance the extra 370 or so lbs. of water under the cockpit. I also have a fume sniffer (propane/butane/gasoline/sulfuric acid etc.) going.
Head w/ holding tank and I also added a shower w/ elec. pump.
-at least one berth with a door: fore or aft, doesn't matter which
Cockpit> Cabin > (door) private head > (door) V-Berth w/ small stand up changing area.
I heated it w/ a 4-8k btu Propane space heater and it was 72F+ inside w/ 0-10F outside winter temps in Rhode Island. I also insulated it w/ the foil over bubble wrap flex. insulation.