That looks great, I'm really liking this design.

Try replacing your headphone_protect function with the following, I think it'll make for a more pleasing shape (I'm using it in my next iteration)....

module headphone_protect()

{

rounded_box( iwidth+5+(2*wall), idepth+5+(2*wall), 1, radius+wall );

hollow_rounded_box( iwidth, idepth, iheight, radius, wall );

translate([0,0,iheight])

difference()

{

rounded_taper3( iwidth+5+(2*wall), idepth+5+(2*wall), theight, iwidth+(2*wall), idepth+(2*wall), radius+wall );

rounded_taper3( iwidth+5, idepth+5, theight, iwidth, idepth, radius );

}

difference()

{

rounded_taper3( iwidth+(2*wall), idepth+(2*wall), theight, iwidth+5+(2*wall), idepth+5+(2*wall), radius+wall );

rounded_taper3( iwidth, idepth, theight, iwidth+5, idepth+5, radius );

}

}

Nice! I'll be uploading a derivative that does away with the stay holes soon. I'm replacing them with holes for the jack. Love the lid! Could we hinge it somehow?