As was suggested by Seeker4 in the previous thread with the same name, I opened a group called The Think Tank. Groups have some limits that make it very hard to have any discussion at all though. Most notable are:
only two levels of replies max
replies may not be greater than 1000 characters
The first can be worked around by replying to the original post with a quote of the reply you're replying to. This is kinda annoying, and combined with the character limit may not get you very far either, as the quote itself reduces the limit.
It would be nice it these limitations could be lifted altogether, or at least stretched up significantly. I can imagine that there are more groups that would benefit from this.