5+ dynamic items of a dimension in column header

Just to clarify, I believe you are talking about when you have a metric and you drag a dimension underneath it to filter:

And the result is the top 5 items:

It's worth noting, that these items, once added aren't really dynamic... if a new page type becomes popular (and has more hits than one of these), using my example above, let's use "podcast", I don't believe it will appear and push one of these out... these 5 items are now locked, the same way that dates in these positions are locked... 

Only dimensions in the left column update based on relevance (sorted by the selected metric).

You can have more than 5 items here, but they do need to be curated.