Have list members seen the xda-developers.com website? One of their number has looked at the code of the "official" YouTube app and has made some changes such that it runs on Android 2.1.
I have installed the apk on my build v1.02 system and it seems to work quite well. Audio and video quality is good although I think there may be a buffer size issue as playback pauses from time to time.
The link explaining things in more detail is http://www.xda-developers.com/android/y ... to-eclair/
Neil