"Why shouldn't it be supported?" - having been away from the Amiga for quite a while I have no idea, but as it seems to be petty politics that's stopping the G-Rex bus board working with AOS4 I thought it was better to ask! Please correct me if I'm wrong about this.
"I guess cnet.device will still work on OS4, if not, could be adapted easily, as the source is included." - I am not a programmer by any stretch of the imagination so would be completely at the mercy of others if modifications need to be made. This however would not seem to be too muchy of a problem as the Amiga community is as far as I remember both talented and mostly friendly.
Thanks for the information.