The PAIA company was formed in 1959 basically but has produced kit synthesizers since 1972 as modular components til the late 80's. In 1974 the Gnome was released, an interesting little box designed originally just to make wind sounds with a vinyl ribbon controller. But other parts were added in to make it more of a theremin type device.
Another great innovation was their use of the 6503 cpu to achieve polyphony right after Oberheim I guess in the mid 70's. They went further and implemented crude computer control along the way on these units and while the Chroma was the first real mass produced piece to implement that I guess maybe PAiA was the first to really venture deeply in to that realm. Here is their site map where you'll find their current product line including the 9700 series modular kits.
Here's a link on building ribbon controllers. Their site has many great articles from old Radio electronics magazines etc.
2700 Gnome P4700(J) Proteus 1 Fatman