RtAudio has had ASIO support since version 4.1, released in October 2002. I don't know why it hasn't been in use in Chuck. As you say, it is the most stable choice in Windows and the only one that easily allows channel counts greater than 2.

Yes, and if you look here;
http://electro-music.com/forum/viewtopic.php?t=18931

You'll see that we have had community-maintained ASIO builds that are confirmed to work and be stable. I've been running these for my live sets, which depend on low-latency and using multiple channels, for over a year and a half now. Just last night I was on stage for about 900 people in one of my country's most prominent venues; in situations like that you can't really use "well, it's a experimental language and...." as a excuse when something crashes as they half expect you to mime over DAT.