It's funny, I was just talking to one of the people that comes along to our electronics club about this earlier on. I think that circuit-bending as it was when this site started is basically dead. No, really.
All the cheap Yamaha PSSes, SK1s and so on are *gone*. People are paying stupid prices for crappy toys that might or might not make a funny noise if poked in the right place, but the really good stuff is just not there. Manufacturers are turning out more and more "black blob" units not to stop people modifying them, but because they are cheap. Casio aren't going to produce a "new SK1", and if they do it will be - guess what? - a black blob board. Why not make it bendable? Because you're too small a market. The sheer cost of producing a new SK1 with components you can actually get at would be prohibitive, simply because factories aren't geared up to make them that way any more.
The Korg Monotron (and indeed the very close relative, the Gakken SX-150) are an interesting development - they clearly *are* geared to our market. It looks like you *are* meant to spindle, fold and mutilate them. So, maybe we'll see a new wave of hobbyist synthesizer constructors like in the 1970s. There are a lot of really cool things you can do with very cheap processor boards (like the Arduino) - things like wavetable oscillators, envelope generators and sequencers. The "boring" bits of the synth are easy, leaving us free to do cool things like filters, waveshapers and oscillators.
It's time to hit those electronics books...