I am a fifth grade teacher in Missouri. The DESE website's released items are pretty much what the test looks like. There hasn't been much change since 2006. As far as the writing expectations...the students are expected to write complete answers in the communication arts portion of the test. If you look at the scoring guide related to the released items, you will see that it says the students have to give a response and details from the text to support their answers. That's something we focus on all year long...not just giving their answer, but telling why they chose that answer. The performance event for communication arts is usually a friendly letter or a journal entry.
If you are using Writer's Workshop, I am pretty sure the scoring guide associated with that program closely matches what is expected on the MAP. If you look at the archived Elementary Writing Prompts it will give you an example of a response which earned all 4 points and an explaination as to why it did.
Another state to look at for good released items similar to Missouri's is Florida. http://fcat.fldoe.org/fcatrelease.asp