You can see a picture of one in the wild, from back the day, here:http://www.vgarc.org/vgarc-originals/in ... -gonzalez/
Object #6 in Appendix image #4 (unlabeled version of the image is earlier on the page).
And a brief anecdote from Alberto Gonzalez, not included in the article-
Mine didn't work very well and I spent a random amount of time (too much usually) turning it on and off until it worked, every day... But it was awesome because I could access the SP700 memory and rip the soundtracks of many favourite SNES games.
And from the article-
The SNES development kit had a MIDI input so it worked more or less like a synthesizer in real time.
Sorry for the random bump, but I found this topic after some brief googling, and thought I'd add this to the discussion.