IMHO its difficult to get a site to average ONE DOLLAR a day....ask anyone who's doing it now.Then you want to do 50 of those? John Reese talked about it, but it is ALOT of work, and documented here on the boards. I think the last person who did a large block of sites documented it ended up making around $2/hr for his efforts once he finally generated traffic. Whoopee. Work on one site at a time, build up traffic until you can monetize to lets say, $50 a day, unless you live in a cardboard box in the third world and a twenty spot will feed your family for the month, then try a second site and so on.
If you have a good, generic domain... then people will naturally type it in. .Com is notiriously known for getting "type-ins" if your domain is good enough. For example.... Someone wants a car. They will naturally type in cars.com instead of cars.info. Type-in traffic happens only with generic domains. I have some generics that get thousands of type-ins / month. It's all in the domain name, to be honest with you. If yah got the generic you get tha ca$h. Still plenty left, if you know where to look