@chimericdream – I would like this too, but I think that it could be achieved through a plugin. In fact, we will probably write a plugin to do that for a new wordpress hosting service we are working on.
I’d have to agree with @edde and @casabsolute and others who have suggested that v3.0 should focus primarily on the merge of WP and WPMU and making WordPress work better with multiple sites/domains.
If efforts were focussed solely on this, it could be a much quicker release cycle than normal…
