Thats nuts, thats going to take alot of traffic and who knows. All depends on your click through ratio.
PR has little do if anything to do with how much a directory takes in. What are you basing these figures on if you don't mind me asking?
Great point, everyone gets so wrapped up with PR. But it's a very small factor in a site's success. The bottom like is there is no formula to see how much a directory makes. It's up to the person. A hard working smart person can make more with a PR2 directory than someone with a PR7 who doesn't know what they are doing.
pr is what people usually take into consideration when buying a directory link obviously you need traffic and good looking temlate etc. but if it's just pr4-pr5 people simply won't pay for a link..