I'm making my own and its much easier to prototype. You just need a source for ceramic.
Here's some from the silver surfer guys. Get the white in the largest size
http://silversurfervap.com/ceramic-flavor-disc.html#
You can use a dremel to shape them, they're a little too big for rbas as they come.
I think I'm going to try that disc idea. Basically a short cylinder shape with a hole drilled horizontally on the bottom side. You could put a coil in there. I'd recommend ribbon kanthal to increase surface area. I'm thinking you can get better flavor by putting the coil within the ceramic and having it heat that up. When you wrap the coil on the outside you can taste the wire.
I really want to get a small solid ceramic coated heater instead of bare wire. It would provide more even heating which gives better and more consistent flavor.
This guy has a source from China who might be able to build a solid disc heater instead of this donut shape:
http://www.fatdaddyvapes.com/donuts.html
Right now the guy has more coming in but he's currently out of stock and the first run was extremely low resistance around .3-.5 Ohms. Next run will be higher.
I want to get a solid disc heater around 1ohm...