It’s true that MultiMarkdown 3.0 no longer includes support for RTF as an export format. But really, version 2.0 never really had good support either.
The first method of converting MultiMarkdown into RTF was actually to create an XHTML document, and then use Apple’s
textutil command to convert the HTML into RTF. This works for many, but not all documents. It doesn’t support images, for example.
MultiMarkdown Composer adds this feature back. You can export directly to RTF, but there will be limitations. And since the actual conversion is handled by Mac OS X itself, there isn’t really anything that can be done to improve or customize the output.
Note:Composer for iOS does not (currently) support converting directly to RTF, but it does convert to OpenDocument.