500 Documents needed

We have a number of websites and need documents writing up for backlinking purposes. We need around 500 documents producing. Each dosument has to have a minimum of 400 characters and can't be copied and pasted from other sources. This has to be unique content.
We will provide text which can be used as a guide-this is not to be duplicated, but re-worded. The winning bidder will also be required to do some research into certain fields.