...Between the email requests D-V get, posts on their facebook page, requests here (they do check in from time to time) and suggestions from myself they have a very good idea of what people are after. They're not living in some alternate universe where they're scoffing at the quality of Aerosmith and the Winter brothers whilst simultaneously plotting to release the complete quadraphonic oeuvre of Ray Conniff.
...If you want to know what's available to them, a little research goes a long way. Take a look at Aerosmth for example - look up their three albums that were released in quad on discogs for example and you'll see that they've never been reissued by anyone other than Columbia/Sony. In fact, the stereo versions of the albums that are on CD currently appear to be the same ones that were released in the early 90's, which would suggest to me that there's a financial or contractual issue preventing re-release - surely someone like MoFi would have had a go by now if it was possible. As for the Winter brothers, you can look them up on amazon UK, you'll see that the majority of their albums have been reissued in the last few years by either BGO or Music On CD. This is what D-V faces when it gets in to the arena of reissuing rock quads, as I'm sure all CD reissue labels do. It just burns us more, obviously, because when they reissue something on CD in stereo we lose the ability to get it in quad. That isn't to say there's nothing available - as licenses expire, new things become re-available on a yearly basis, but you have to work with what those things are, not to mention compete with other labels to get them...