It may be a short list, but it s available. Between the different list houses there are also significant differences in pricing, return policies, and freshness of lists and names. Some vendors clean their lists more frequently. Different vendors offer different service levels, too. Each list house has its own counts and numbers for different selections, and each treats merged data in different ways.
Most list houses have their own particular specialty - so it pays to shop around.
When you need a great mailing list, just dig.