I did do this about 10 years ago with my oldest. I bought the Kingfisher History Encyclopedia and everything just like they tell you to in WTM. While it went okay, I don't feel like she ever had a good handle on it. Because I had a 1 year old and a newborn, I just wasn't able to give her the guidance she needed. If you have a child who is already experienced with outlining, I think it would be a valuable tool.
If you are wanting this as a springboard to writing, you might want to look at Writing With Skill. It is also from the WTM writers. It is directed at the student and holds them responsible for following directions and doing the work. I have looked through the first volume and I like it very much. It uses the same methodology as outlined in the WTM, but it is a little more hand-holding for the student at the beginning - meaning it actually teaches them how to outline and it really walks them through it step by step at the beginning. They have an extensive sample available on their website. I think it is about 7 weeks worth of lessons. I love the look of it and was so anxious to start it, but I decided my 10 and 11 year old needed a little more work on dictation and narration first so we are going with the last books of Writing with Ease, which is the series that comes before Writing With Skill.
While I don't love everything about the WTM model, I do think that they have very solid ideas about writing instruction... especially for kids to whom writing does not just come naturally, the kids who are more of "part to whole" learners. I have had kids of each type and some need more hand-holding on the writing instruction.
Also, in their last volume of SOTW, the modern history one, I know that they do the same kind of walking through outlining thing with the students. I'm sure you can see that in a sample as well. While I wouldn't necessarily use it for my history curriculum, I might buy it strictly for the outlining/writing portions if that was really important to me. You would need the activity book as well.
So, that was probably way more information than you wanted, but hopefully something will be helpful to you.