I've made QS-encoded CD's, for my own personal use, from discrete sources, using Involve's encoder, in the "Smart Encode" mode. They sound excellent when played in stereo, and are nearly indistinguishable from the original when played through the SM. They also sound great when decoded with PL2.I would rather the CD layer have the QS.
Actually the fold down of a QS recording IS the QS recording. To have a multitrack that mixes down to good QS, the multitrack has to be compatible with QS. Making a separate "fold down" would be superfluous because the QS mix serves the same purpose.
I want to buy a simple CD or LP, not a bunch of layers I will never use.