A lot of those pieces were composed a long time ago, but it would be possible to make modern recordings of them. That would cost money, though - you'd have to hire musicians and set up a recording session, or pay to use existing recordings (which might not be suitable, if they don't adhere to a strict beat). Getting the rights to new music would likely be more expensive, too. These are so old that if they still have to pay royalties on them, it probably isn't very much. That's why clubs that have modern lists can't sell compilations of their recordings - the music belongs to the artists who composed and recorded it. The best I've got so far is to choose a few selections off one of the modern lists, buy the tracks on iTunes, and make my own playlists for each dance. I honestly don't know of any modern instrumental pieces that would be foxtrots or waltzes, etc. Modern dance music is generally more for club dancing than ballroom. I've checked out modern commercial recordings meant for ballroom dance studios, which would include instrumental arrangements, but, unfortunately, their tempos aren't always correct for our pattern dances.