If the problem is the width of the sleeve at the cap, is it possible to cut a slit down the center of the length of the sleeve then insert a V shape of batting and backing (lining fabric) in a quilt as you go technique? Rather like putting a gusset into a garment to make more room. Another option (possibly on a different garment) is to use Nancy Zieman's technique which you described then adding length to the sleeve in this QAYG method.
I've successfully lengthened a sweatshirt jacket using this technique and in the final garment there was no indication that it had been done....and I did it after the main garment had been quilted and cut...