First of all I would like to say that I think 3.0 is a great step forward for wordpress.
I hope this question hasn't been asked before, I couldn't find it on first sight, but the alpha/beta category isn't really very clear with all those old alpha/beta releases in it.
So, my question, is it possible (with not too much core hacking) to remove the or some default post types? For some set-ups it would be nice to be able to remove posts and replace it with a custom thing. (Or extend default post types?).