Another alternative in recent versions of OS X is using the macbinary command from the Terminal application. (http://developer.apple.com/mac/library/documentation/Darwin/Reference/ManPages/man1/macbinary.1.html)

It can be used to convert a single file into MacBinary format, which can be loaded into Mini vMac with ImportFl, and then decoded with binUnpk or Stuffit Expander.

A disadvantage is that this only works on a single file at a time. And also that you need to use command line.