You know, I've been trying not to think about the cost...
I'm using a Sherline Mini Lathe, only 14 inches in length and designed to do very detailed miniature items.
I also bought the parts to turn it into a Mill when I need to.
By the time the mill ends come in it will have set me back around $2370 Canadian, or about $1850 US. It took two years to save for it.
To turn it into a CNC unit would cost me another $1600 bucks. So in another year I can start popping out sonics.
As to sound, It's designed so that the core of a C.O. toy slides right inside. You can find sound chips that will fit into a sonic all over the internet. The hard part is finding a small enough speaker to fit. Oh, and you usually have to buy a lot of chips 50-100 at a time.
I guess we could post an interest run for a sound kit for sonics? or Russ could as he already has a source for them...