Well, here it is another six months later and I still have no release. Besides being very busy, I can't get unrar5 to work with unicode/utf8 properly.
Do you guys even give a crap about RAR? If I could decode all the C++ wrappers in 7zip to just add its unrar to the existing LZMA stuff, I'd try that, but I'm quite bad at following that code for some reason and have never figured it out :(