:)
Nomad Factory. It's probably been ported, but the software itself was release sometime before 2004, AFAIK. Doesn't mean it isn't good, just that, it's possible that it isn't entirely up par w/ to more recent equivalents. I'm not a huge fan of NF plug-ins, anyway.
The ABG stuff seems to be cutting edge - a bunch of tone maniacs w/ a passion, really dedicated to creating the best possible sound in an amp sim. Maybe someday if they port to Mac, I'll be able to try it for myself.