She's on a pretty tight budget to put this costume together so a real leather jacket is out of the question but I think I've found a pattern for a reasonable facsimile of the jacket (with a few minor modifications).
The pattern I've settled on is Jacket Pattern 4305 by Lekala sewing patterns.
I think with the addition of patch pockets on the bust it should work for the cosplay.
Now to tackle the actual making of what is possibly the most complex garment construction project I've ever taken on.
This one definitely warrants making a trial version before cutting into the more expensive pleather (or whatever I end up finding/buying for the real version) so I'm off to the fabric store.
I'll keep you updated on how this one comes together. Keep your fingers crossed for me.
K