[Pharo-project] VM more flexible for research?

Hi folks. I am a newbie for both research and VM. However, in the little time I have been working on this, I always need some extra bits in the object header to do some experiments. And the problem is that I always have only one :( So I come to the idea of having a more flexible VM for the people that want to experiment with it. The first idea was to remove compact classes. But of course, there may be much more ideas or things to do. What do you think? Cheers Mariano