There aren't nearly as many legitimate ACT tests out there as there are SAT tests.
This is incorrect. There are just as many legitimate ACTs (if not more) than SAT QAS out there. In total, there are 16 SAT QAS from the new SAT (starting in March 05). In total, there are more than 20 legitimate ACTs (April, June and December from every year) out there. However, despite being more numerous, legitimate ACTs are much harder to find than SAT QAS, in my opinion, since ACT doesn't make them as readily available as SAT does. For example, there are 10 SATs in the Blue Book, while only 3 ACTs in the Red Book.