Yes, there are.
Take a look at a log file:
2008-02-22 19.22.31.406:INFO :Item "187:003882" eligibility from STRICT to NONE - [SELECTED].
2008-02-22 19.29.46.015:INFO :Item "187:007298" eligibility from STRICT to NONE - [SELECTED].
2008-02-22 19.44.27.750:INFO :Item "188:007554" eligibility from STRICT to NONE - [SELECTED].
2008-02-22 19.52.22.421:INFO :Item "188:000009-01" presented
2008-02-22 19.52.31.031:INFO :Item "188:002967" eligibility from STRICT to NONE - [SELECTED].
Look at the indexes, I'm assuming there are about 10,000 questions. And, given that the software gives you Quant and Verbal scores that range in from the bottom 2nd percentile to the top 99th+, they have to have a lot of questions for each level. It's not hard to deduce that there are at least a few thousand questions. And everytime I do a new GMATPrep, I always see new questions (especially brand new SC's in Verbal).
And it was far more than 20,

Let's just say I learned my lesson. I'm writing it sober and well rested and aiming for the top.