Bill,
Why would anyone want to have a mast that slides back and forth on the beam? That's ridiculous.

This all started with the question as to whether wings will have essentially the same effect, as far as righting moment, as having a wider boat.

Luiz said, I believe, that it will increase the righting moment but it will be offset some by the wing on the opposite side. He added that the real benefit of a wider boat is that the leeward hull (being farther away from the mast) plays a greater role in reducing heeling moment than it does on a narrower boat.

So I conjectured in a totally non-serious way, that the only way to make a narrow cat act more like a wider cat is to have a hiking rack only on the windward side to increase the righting moment and also slide the whole mast to windward, so the leeward hull could help to reduce heeling moment.

For instance, the difference in width between a trailerable boat and a Tornado is 1.5 feet. So if you slide the mast to windward 9 inches, you would have, in effect, a 10-foot wide boat on the leeward side because of the increased distance from mast to leeward hull, and (at least)a 10-foot wide boat on the windward side, as well, because of the ability to get crew weight out farther.

And all this is assuming that you are sailing in enough wind that you NEED to increase righting moment and reduce heeling moment.

I haven't yet asked the question as to whether wider boats have an advantage in light air where all these "moment" things are not an issue.