Godowsky wrote a Passacaglia on the opening theme from the Unfinished.
I have not heard it but there are a number of recordings about.  I'm told
that it fits snugly into that tradition (which I love) of grand pianism
that contains the better works of Liszt, Busoni, Sorabji et al.  ...
(which people who know me know me for a fan of...)

It consists of 44 variations, a cadenza and a fugue (according to the
Fischer edition of 1928), and in one performance (de Waal's, on Hyperion
CDA66496) lasts just under 17 minutes (a recording with other works by
Godowsky, Schubert, and others, perhaps all arranged by Godowsky? Not
sure.) I believe Hamelin recorded the work for Musica Viva in 1988- yes,
he did; another source confirms it (and his recording lasts 18:36- Musica
Viva MVCD 1026, I don't know if this CD is available anywhere for sale but
UC Santa Barbara has it (just checked amazon, which I admit to having a
financial association with- I maintain a website- not the one below- that's
an amazon associate- but they're the first site that came to mind, anyhow-
and this CD was there, so it .Is. still available), Grante's CD Altarus CD
9094 has it, Sherbakhov's series on Marco Polo should get to it (spelling?
sorry), a CD on Hobson's new label Zephyr (best known to me for its ongoing
series of Moscheles piano concerti) has it (Zephyr 11298), Grante's Music
and Arts CD 984 (a less recent CD than the Altarus one) has it..  it seems
often enough recorded, yet I alas haven't heard it:(...(and want to!)

Sorry I can't be of more help...

-Eric Schissel
http://www.lightlink.com/schissel ICQ#7279016