Aha! Arensky, you were here as well!
Visit
www.rprf.org, where you can download some roll catalogues, including Welte. I don't agree with some of the stuff on that website, and the catalogues have been superseded by other more accurate and complete ones over the years, but they are a reasonable starting point.
As I said just now in the new topic I posted under Performance, player pianos have suffered over the years through being in the hands of collectors. People have wanted them because of their mechanical quaintness, and they have been far more interested in polishing them than listening to them. The same goes for many museums of such instruments, alas.
Recently, it has become possible to scan piano rolls, which means that new copies can be made that are absolutely identical to the originals. This in turn means that the repertoire is more generally available, so that those with the best pianos can also obtain the best rolls, which was not necessarily the case before.
Over 1600 Welte-Mignon titles are now available from a friend of mine in Germany, Tom Jansen, and his catalogue is growing every month. He is at
www.maesto.com, in case you are interested. My best friend, Denis Hall, in London, has the finest Steinway Welte grand that I know, and he is gradually putting a whole range of pianists and composers on to private CD.
To answer piano121, they certainly did play other repertoire. I put a recording of Carl Reinecke playing Beethoven on the webpage at
www.pianola.org/reproducing/reproducing_welte.cfm. But I'll post a couple of pre-Romantic pieces here. They are the Prelude & Fugue in F minor from Book 2 of the 48, played by Raoul Pugno, and a "Pièce de Scarlatti", arranged and played by Granados. Carl Reinecke was the earliest born pianist to record for roll, having been born in 1824, three years before Beethoven died. He was an expert on Mozart, and the way he plays it is very different from what we expect nowadays. I'll see if I can post some in due course.
Between us in the Pianola Institute, we have around 15,000 music rolls. If you include the non-recorded Pianola rolls, which are the majority, there is some remarkable repertoire. I could play you Arcadelt (OK, I admit it's arranged by Liszt), Byrd, Palestrina, all the 48, the Mozart Requiem, the Beethoven sonatas, oceans of romantic stuff, Bruckner, Mahler, Smetana's Moldau, all of Mastersingers (on 36 rolls), the complete Debussy Preludes, Widor's Toccata, Schoenberg, Marcel Dupré, the main Stravinsky ballets (see
www.pianola.org/history/history_stravinsky.cfm), Nancarrow, Cage's 4'33" (on three rolls), Arabic music, and so on.
But it's 1.30 am, and I still have work to do. That's all for now. Thanks for the interest.