The Folkboat design as liveaboard cruising boat has come up before, but the discussion went off topic only after writing it off for its lack of headroom. The Top Hat and Clansman were offered as alternatives. I just want to add my two cents worth.
Having owned and cruised and livedaboard a Top Hat and now owning a Folkie which I have sailed offshore a little. The Folkie is head and shoulders above the TH; better looking, stiffer, faster, and more willing to steer itself. The Clansman is way too expensive for most guys who sail alone.
In addition, I hold that it's the sailor, not the boat, that's critical: read "Dove", or "Tinkerbelle" and so on. Every mooring field the world over are full of large unused yachts, too big or too costly to sail regularly. Sail what you've got.

As a concept, for singlehanded coastal cruising, which would you choose?

These guys seem to have done ok in a small boat. I have a few reasons for preferring a

smaller vessel. Cost not the least. Any thoughts re folkboats.