Regarding the Casio Portable Keyboard (teaches songs with key lights), Model LK220AD
http://www.bestbuy.com/site/olspage.jsp;jsessionid=15YKQNWQ11OOLKC4D3EFAFI?_dyncharset=ISO-8859-1&id=pcat17071&type=page&st=8885664&sc=Global&cp=1&nrp=15&sp=&qp=&list=n&iht=y&usc=All+Categories&ks=960
product # 8885664
..the teaching feature seems desirable, though the window that relates which fingers to use for which keys is so small it seems you almost have to use peripheral vision to hit the lit keys.
What I'm wondering is: can you have some one who CAN PLAY program-in a song (that's not on the list) so that it'll play with lit keys (and the novice can learn it)?
Also..."General MIDI compatibility"...in what ways? I'm assuming this means settings for a given sound or tonality? One can download them into this Casio keyboard? Or simply set them in a similar fashion?
What I really am looking for is a "teaching" keyboard in this price range which you can either program with new songs...or which will accept new songs (with accompanying lighted-keys directives) via download as, say, one could download Karoke (sp?) pieces along with visual accompaniments (I assume this is possible for given Karoke players?).