Liszt's "Variations"

[Ruro]

 Lo all,

 Like ya do, I was following interesting link after link, and ended up on the Wikipedia page for Liszt's Totentanz, and at the bottom it says: Besides these [Revised Totentanz Versions] a two piano as well as a solo piano version by Liszt can be found.
 How often did Liszt make all the variations of a piece, not of the music itself but instrumentaly? I can understand he did it with this one, since it seems quite a feat of a piece for him personally, so maybe he would go to such lengths, but how often was this done? And did other composers write different instrumentally arranged versions of there "master works"?
 I never even heard of the recordings existing... neither seeing them listed with the "S" or "Opus" systems of works.

 Thanks for the info in advance