Success. #renoise x86 running under FreeBSD 11.1-Release. JACK for audio, no MIDI. Possible with FreeBSD's Linux ABI support.
Renoise x86_64 should be possible; I'll need to compile a copy of JACK1 in a CentOS 7 64-bit environment and try it.
I'd done this previously in a jail, but it runs much better without having to remote X.