Letting us write songs would be like letting us actually put ore into the furnace, shape the ingots by hitting it at different angles with different hammers, quench the metal, shape the rivets/plates and put the whole thing together...far above and beyond the type of game runescape is. Also that music skillcape has been floating around for...it has to be 4 years at least? I wouldn't bet on anything coming of it anytime soon. I would work sort of like any MIDI input program - you'd have a simple interface, with the y-axis being the notes - 0 would be A0, 8 would be A1, etc. The x-axis would be how far into the song the note would be, or when the note would be played. You could draw the note in yourself, and have maybe 32 bars to work with? You could then write short, simple, songs or melodies (32 bars at the tempo of the song I mentioned above, Stranded, would be like one minute and fourty-five seconds or something). It's a tad difficult to explain, but the best way thing I can say is look up how actual music-making software is designed. I use Reason 6.5, a professional music-making software, to make music, and the interface is actual somewhat simple. I have recreated many Runescape songs, and I have the MIDI files for about 500 of them. There aren't a whole lot of instruments going on in these songs - referencing Stranded again, there's the "crystal" synth, a pizzicato, two string sections, a drum, a French horn, two pads, (pads are like synths but are very wide and atmospheric), and a cymbal. These instruments are used in many of their songs, and if they put the transposed samples (or "live" samples, might work better) into the game, people could simply draw in notes, and have a song that uses the same instruments as the game's official soundtrack. I've never played Mario Paint, but I hear it has a somewhat similar interface in its music part, if that helps you visualize what it could look like.