Turn $1320 into $3000/mth?

I have made a couple checks in the offline world since joining it but after reading up on the rent-a-site model, I would like to explore that further.

Basically, you build a site, get it to rank highly on google, and then rent it out to a business. You would do this for local businesses such as "new york general attorney" or "los angeles construction company".

First is keyword research and I won't tell you exactly how I go about it but once you find a business domain available you would see how many searches there are in the google keyword tool.
I am shooting for exact match keyword domains with over 100 searches per month. Also, I want to evaluate the competition for that keyword so that I don't try to compete with a site that already has 1000+ backlinks for that term. From now on, I want to be more considerate of this.
Then,
You register an exact match domain name so like LosAngelesConstructionCompany.org and then build a site on it with a couple articles optimized for search engines for a term. There are other on-page seo things to do as well.
Then you would build links to it depending on the competition's backlinks. You should easily rank an exact match domain name in a few weeks with some backlinks and even without them but it all depends.

Now I have done this for 2 sites and I started just a few days ago. I did it with MiamiFamilyLaw.org and LosAngelesInteriorDecorators.com.
I already have someone interested in the LA interiors one and am working to build some more backlinks to the miami family law one but really it is just a matter of time with these exact match domains.

I also have Matt W Rhodes' 4 hour outsourcing wso which is very good. I now want to apply that to this rent-a-site model.

Here is a brief plan which I will refine later:

Say I hire 5 workers at $5/hour and each works 40 hours a week. I can have them build/rank 8 sites a week each putting me at 40 sites per week. $1000/week is what I pay plus the 40x $8 for the domains. This is a total cost of $1320 for the week.
Now I have 40 sites that I can rent for $100/month each. I could hire commissioned based sales people or even hourly sales people. Let's say I do it on a commission of $25/month just for example purpose. A good thing with this is that if the business cancels, you only pay when the sales person has the site rented out.

By paying the sales people, I really get 40x$75=$3000/month. The outlay was $1320 and I get $3000/month. Let's say I just had the sites built for one week. That is a $1320 investment turned into 12x3000=$36000/year. Imagine having the workers fulltime pumping out 40 sites a week for $1320. Every $1320 turns into $3000/month.

This plan requires some investment, but you really don't have to work too much besides managing it all.
It is very scalable in that you could:

• reduce hourly pay of workers to decrease cost
• increase # of workers to pump out more sites
• increase productivity of workers to pump out more sites

Also, you don't even need to rent out ALL of the sites to break even.

THIS IS ALL THEORETICAL BUT IS SOMETHING THAT I HOPE TO MAKE PRACTICAL IN THE COMING WEEKS AND MONTHS AHEAD.