Unless I’m missing something - the Subject says it all. We’re limited to 1, 2, & 4. Sigh. . . 
I think John Barron in his last video shows the option to make it 3, but I might as well be mistaken.
John B mentions three-bars in the measure-repeats section, but he does not show how to do it, and the properties do not give the option for a three-measure repeat. So I think he may have meant that one could have the repeat measures counted off at three-measure intervals.
If I am wrong, I really hope John will show how to do it (although in my case, this is just idle curiosity speaking).
How about p27 in the version history ?
Nice one Marc, but you have to link to it or someone grumbles they can’t find it 
I still don’t see how to start a 4-measure repeat with a three-measure repeat even after checking the Engrave Option.
(I don’t know why I care, since I’ll never use this; but I’d still like to know how. Ego, perhaps.)
It’s not a four-bar repeat: it’s a one bar repeat, grouped into fours, and then with the first incomplete group of three bars shown as a three-bar repeat. See page 27 in the Version History document.
Okay, I got it to work (more or less stumbled on it, actually). I had read p 27, but apparently the order in which one does things has an effect.
Thanks, everyone, for your patience.
Daniel - Any chance of getting a three bar repeat? %3?
I’d be interested to hear more about the situations in which you’d like to use a three-bar repeat. We didn’t add it because we’ve never come across it in any literature and it seems like a recipe for confusion, but I’m open to persuasion!
Would be great to have a three bar repeat for a piece I’m doing now, which is based on a repetitive three bar pattern. It would save a lot of space in some of the parts (especially the drum part) and make it much clearer. But it’s quite exceptional I guess, doesn’t happen all that often…
5 bar repeat, 7 bar repeat and so on would be nice.
How is that a standard? I have never seen this notation… It’s rather unlikely that the devs implement such a thing, but who knows…
One and 2 bar repeats, properly used, are standard. Anything else is bogus notation. Refer to Clinton Roemer “The Art of Music Copying” for examples of clear, professional layouts.