Yup I know that feeling! (6'2" and a bit ish)
On top of the posh workmate with all its legs down seems to be a nice working height though.
It was fully enclosed, with possibly a small vent toward the top. That way the dust gets caught in the airflow and collected. You probably want the vacuum outlet near the base.
I can't remember which video it was, but I was watching some of the examples here:
and one showed a good internal shot of his router table with under collection. You can see from the example videos on thing like the circle jig that it does do a very good job collecting
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