What is the movement like? With no ballast in the keel, is it not somewhat rolly?

The OVNI is much more stable than you would expect, and it is not at all rolly. As to the yard not letting you see the stability curves... I would guess they didn't do it, simply because they may not have that kind of detailed information! This business of stability in cruising yachts is, honestly, most of the time a red herring. None of the production cruising yachts that I know of have been properly tested in a tank, so that mythical "stability factor" depends primarily on calculations, which, at best, present only one side of the argument. As I stated above, the stability of a yacht depends as much on its inherent stability as on a host of external factors: wind, sea state, etc., etc. There are certain situations when even the most stable yacht will simply flip over... I took my own OVNI43 to the Antarctic, crossed the Drake Passage in 50 knots+, while last summer I sailed on an OVNI 39 to 80°N... and slept very well on both occasions!