ESL itemwriting

We plan to publish an elementary-level ESL textbook for Japanese high school students, and are in search of an item writer with adequate experience of similar projects. Please find the attached file for sample articles.
We need 14 articles, each of which consists of 150-250 words and focuses on one grammar topic. We need a variety in styles (fictions, descriptions, essays etc.) and topics, but writing and vocabulary should be kept quite simple and easy, which can be the toughest part of the job.
Some revisions might be requested with additional payment.
We appreciate your interest in our project.