This was also suggested.

http://www.tobias-erichsen.de/software/rtpmidi.html

I hope to give these a try soon. My main motivation in all of this was to be able to try RealBand, which so far is only available in the Windows version. And my motivation in wanting to try that is a need that I have to make a bunch of reasonable cover versions of songs in which I can play or drop out the melody line (or sometimes another instrumental part) and play it back at different tempos. It's a bit like making Karaoke arrangements, but not as demanding of realism.

I've been real happy with the BIAB Mac version. I suppose I could consider just separating up a separate Windows laptop, but I travel a lot and want to share files to the Mac side, so that would be awkward.