Yes, it is. Its fascinating to watch someone 'play' one, and I can't work out how on earth they control the pitch.
Very interesting clip here: http://www.youtube.com/watch?v=Woc1_8Fo2Q4 (Look out from 1:23 for the saw!)
I really like Daniel Melingo: his album Santa Milonga has some very good milonga tracks, and a couple of good danceable tangos too (but not really wedding dance stuff). He provides vocals on the El Gaucho soundtrack too (another side to Muller & Makaroff - nothing like their Gotan stuff), and a very successful tanda can be made from the two versions of Andres Retamal (the track with the saw & the remix), sandwiched between Comodoro Rivadavia I as an interlude.