I think I have sent you PM a while ago, but the house across the road from us (DCP) was taken off the block a few years ago and a new house built.
A house across the road from an IP we have in Coorparoo has just been taken off as well, and a new house is being built. It was one of a row of three pre-war houses. So...... they certainly can be taken off, if you know the right people it seems.
We were told that our IP could quite possibly be approved to be taken off the block. My impression was that we would have less chance than a developer who is doing this all the time. Of course, this means nothing until we try it, and we don't plan on doing so, but it seems as plain as the nose on my face, that the two that I know have been taken off are indeed "gone" so DCP was able to be worked around in at least two cases local to me.