I can't say there isn't Jack but I can't think off hand of other abc software like that.

I think the main area of sound quality is more likely to be in the "synth". I don't know how Phil worked his but for the midi route you are always at the mercy of this component (and with programs like timidity you can spend a wile trying to find reasonable sound fonts - I think I settled on Merlin Gold???). Timidity will do midi->wav - that was just piped to lame in the previous example. Something like this for a wav:

$ timidity infile.mid -Ow -o out.wav