The boat you are after is very close to the same boat I would be after today if I was in the market.
My intern right now, Will, is doing a custom 26'er for me. We'll post the results of his work in a week.
I look forward to checking that one out. I'm also a fan of 27-30' boats for cruising.
Jackett: It doesn't meet the offshore requirements of your list, but the interior layout of my Pearson 28-2 (same layout is found on a Bene First 285 and some other boats) is very functional for a boat this length. You get two double beds at opposite ends of the boat (V-berth and double quarterberth) without anyone sleeping on the table, and the galley is a decent size. The trick is pushing the head aft and the table forward to put the head and galley at the widest part of the boat. I also hate moving furniture around at the start and end of every day. The settees are also comfortable enough to sleep on, should both kids not want to share the v-berth. I've spent a week onboard with 3 adults and it's been pretty comfortable, but haven't done it with 4. A downside to this design is that getting a double quarterberth under the cockpit requires a bit more freeboard than I'd like.
How much vertical room do you have between the aft berth and the underside of the cockpit sole? Is it enough for the person sleeping on the inside to sleep on their side without their shoulders getting jammed? Its close to my ideal layout for slightly larger boats, but on the design I'm working on I just can't seem to get enough room, while maintaining a deep enough cockpit to feel comfortable at sea, without the headroom getting silly.
I've played around with a transverse berth, on the basis that a bit less vertical clearance over your hips is better than not much vertical clearance over the head and shoulders of the person sleeping on the inside. But of course, that pushes the waterline beam towards being wider to get a long enough berth, which I'm not keen on.
May well end up with your layout, but reduce the aft cabin to a single berth to allow the cockpit to be deeper, and accept that with 4 on board, one person has to sleep on the settee berths. I do like having all the 'wet' areas that get accessed regularly at sea (head, galley, chart table and oilskin locker) handy for the companionway, and keep the rest dry. However, I've ended up currently with a more traditional layout of galley and chart table aft, heads between the main cabin and forecabin, in order to push the saloon aft to the wider part of the boat where there's more room - that way the settees, which also form the sea berths, can be parallel with the centreline, which works better. But I am very tempted by your layout, if only I could get enough headroom over the aft berth.