Has anyone tried making an insulated jacket from a fleece pattern? I'm thinking a fairly thin synthetic insulation (I have some Thinsulate Platinum J80, kind of similar to Primaloft) with a light nylon shell.

It seems as though you could assemble the pieces separately, then sew together like you would the fleece. It wouldn't be elegant, but would be a lighter alternative to fleece. It should be easier to sew, and I have a fleece pattern that I know fits.

I normally take a light down jacket and a fleece, as I like the idea of having one synthetic insulating garment in case the worst happens and everything gets wet. My homemade fleece weighs 13.5oz., and I think a synthetic jacket like I'm describing would be quite a bit lighter.