I'm not sure I believe in such a thing as an absolute mis-match between a particular song and a particular instrument. I think you can play just about any song on just about any instrument, as long as you accept that your choice of instrument is going to change the way the song is perceived. In some cases it's just funny, like the aforementioned Rachmaminov piano concerto on accordion, or the old Martin Mull rearrangement of "Dueling Banjos" for tuba. In other cases it can add a dimension that clearly isn't there with more conventional instrumentation -- Hendrix's rendition of "The Star-Spangled Banner" on solo electric guitar is a stunning example of that. Of course, you have to be prepared to bring a certain amount of creativity to your arrangement if you want to reap the benefits of such re-interpretation.

Sometimes unorthodox instrumentation can really surprise you. I used to have a record (vinyl) by the classical guitarist John Williams "and friends," playing baroque and classical pieces in an ensemble of two classical guitars, two marimbas, and bass (upright). I've never run into this combination before or since, but it was so beautiful it could make you weep.

I have lately been experimenting with a few solo fingerstyle guitar arrangements of old pop tunes, with some amazing results -- "Leader Of The Pack" in DADGAD tuning (with corresponding pseudo-Celtic flourishes) is one that has worked quite well. And you get the added thrill of watching the audience gradually recognize the tune, which is great fun.