Any play who can run 150 balls in theory can run 1000. The real challenge is keeping your focus for that long. The high run record is more an indicator of endurance/luck than it is skill.
I was going to post pretty much the same thing. Except I think 150 balls is low. I'm not sure where to draw the line exactly but I would guess it would be around 300ish. If you have the skills to run 300+ several times, it's just a matter of putting in the time and having the right amount of concentration to break the current record.
For example, if we went through Jayson Shaw's high run and picked the 5 most difficult racks, I would bet any 750+ fargo is a heavy favorite to run all 5 racks. So it's not as much a matter of skill as it is a matter of concentration, luck, handling pressure, endurance, etc.
It's kind of like if you took a 650 fargo player and asked them how many 5 FT stop shots they could make it in a row. Any of them can make 50 in a row without much effort. But they would need a crazy amount of concentration to make 300+ in a row. But the 300+ run doesn't really involve any extra shot making skill.