Hi Jeremy (?),
I "kinda" have an answer, but not a very good one. I guess you will know what I mean when you see it.
First, I created a calculated metric that used the IF function and basically set the Visitors (but it works with any metric) to 999 billion when the original value is below x (150 in my example) and just copies the original value when it´s above 150.
Then I sorted the table by visitor (ascending) and limited it to n rows.
On the plus side, you actually get a table that shows the bottom n rows with more than x visitors.
BUT: when you sort the table with any other metric than "modified" Visitors, it goes belly up.
Actually, I don't like my solution very much.
If I were hard pressed, I probably would run a report in Excel using the Report Builder plugin.
I'm looking forward to more creative solutions than what I cobbled together.