[uxp]

MacRuby is currently listed as a Private Framework in Lion. If it stays that way through release, submitting MacRuby applications will require you to bundle MacRuby with your application, or else risk being rejected by Apple at the Mac App Store.

[acl]

That's true. Bundling MacRuby with your application is easy though, and doesn't take up us much space as you might think. My MacRuby app, together with the MacRuby framework and a couple of embedded gems, takes just over 10MB GZip'd for download. Obviously that's heavier than it would be without the embedded framework, but I don't think it will be a deal killer.

Even if Apple does switch MacRuby to a public Framework in Lion, my guess is that MacRuby will evolve quickly, and many developers will choose to embed MacRuby anyway to be assured of the latest version.