No plans, but here's a rough idea from rec.woodworking:
" If I were building it, I'd consider making a laminated tube.....start
with a form equal in size and shape to what you want the inside of the case
to be... around that form, wrap whatever your liner material (velvet,
velour, satin, etc.) around it... then wrap whatever padding (if any)....
then, I'd layer heavy paper (like an .020" phenolic paper backer). make a
wrap and glue the seam with contact cement... coat the whole tube with
contact cement, and wrap another layer of the paper... continue until you
have the desired wall thickness...and stagger the seams. Finally, glue a
veneer of your favorite species to the outside... finish as desired. "