Regarding the Steinberg/Holst, I am very familiar with it and have a copy of it including an "AMbient Surround Imaging" (AMSI) version issued by DGG/Universal that I found on a trip to London some years back. It is a process developed by the EMIL-BERLINER-HAUS,HANOVER. The series, if you are not aware of it is called "eloquence" and appeared on the market in Europe shortly after Universal Classics took over and includes recordings from the DGG, Philips, and Decca/London catalogs. I don't know if they are available here in the US.
Now, the Steinberg might be too early, but DGG did do some Quad sessions. They were never released in Quad (similar to the series of Quad recordings that Philips did but never issued in Quad that are now being issued in 4.0 SACD hybrids by Pentatone called "RQR"). But, if interested, the famous Kleiber/VPO/Beethoven 5 was recorded in 4-channel. There is suppose to be a release in DVD-A which preserves the original. I have recently read there is also an SACD (not a hybrid) that also preserves the original; in case you are interested.