Fantasy Sewing: Winter Coat

I bet you thought I wasn't going to post today, didn't you? Honestly, I thought I wouldn't post today either, but here I am! We're going to call this post Fantasy Sewing, in honor of Tanit-Isis, whose blog I absolutely adore.

I do a lot of fantasy sewing. I do it the most when the weather takes me by surprise and I'm wishing I already had a very specific beautiful garment in my closet. Today, it was a winter coat. Now, I know that it's not quite cold enough for the coat I'm dreaming about, but the weather today reminded me that winter is coming. In a Song-of-Ice-and-Fire kind of way. Minus the dragons. Winter would be so much better if there were dragons. :)

So, I don't know how many of you were reading my blog last year when I wrote about coats, but I've been fantasizing about this specific coat ever since then:

This is the year, guys. After I'm done with the dress I'm working on (admittedly, this may take a while), this coat is next on my list. With maybe a small detour into Renfrew-land, because I'll need something quick and easy after the Couture Dress.

How am I going to make it, you ask? Ummm.... I haven't quite figured that out yet. I also haven't figured out the fabric. Mustard is a terrible color for me, so I initially wanted a navy blue coat with a jade/seafoam lining, but I'm afraid that navy will drown out all those lovely details. So...maybe jade/seafoam wool with a navy lining? Except that I can't seem to find the exact shade of greenish blue I'm looking for. Remember the Pantone color Cockatoo? I want something like that, but maybe a little bluer? Am I asking too much? Is that too springy and not wintery enough? Should I just go with navy? Or maybe red?

The other problem, and of course, the more obvious one, is that there's no pattern for this coat, a fact which leaves me facing the possibility of drafting at least part of it. This is incredibly scary, so I've been looking for a pattern that covers at least some of the coat's aspects. This is the closest I've gotten so far:

 

Butterick 5425. It has princess seaming that goes to the shoulder instead of the sleeve, and it looks like that white one has a distinctly puffed sleeve. Maybe not, looking at the line drawing: 

 

Things I'd have to do to this pattern: add yokes at the shoulders, add a waistband, remove the skirt of the coat and draft a new one with full pleating, cut the sleeves off just below the elbow and create that gorgeously full pleated sleeve. That's a whole lot, but I have yet to find a pattern that's any closer. Have any of you seen a pattern that's sort of similar to this coat?

The one thing I have figured out is how to make this coat truly winter-worthy. Have you seen the lambswool interlining Sunni's added to her shop?!? So expensive, but so exciting! If I'm going to spend the time and effort making the perfect winter coat, I'm going to spare no expense to make it the perfect one that will last forever and keep me warm in the coldest of weather. What are your thoughts? Have you used lambswool interlining before?