I've been asked by a friend about building a resonator ukulele for him and have starting researching what goes into building one.
In a resonator you don't want the "box" adding to the sound so it's "over-built" compared to a standard instrument. In this way the cone gets to generate all the sound.
I've found multiple sources for cones and coverplates, from National, Republic, Delta and others.
At this point I'm leaning towards either National or Delta, I figure if I'm putting the effort into doing this right then I don't want to go too cheap. Also, these two are interchangeable (if I specify the size correctly) so it's easy to swap between them later if desired.
The other piece I want up front is the sound well that the cone sits on. There are several ways to go on this but I'm looking at tubular plywood, like a drum shell or tambourine ring, to support the cone. I've seen this done for guitars and it will really support the cone while also locking the top/back together to stop any unwanted vibration.
Once I get these I can work on the rest of the design to get body size and neck angle correct. I'm thinking about sizing this to fit a specific case and hoping to make it a soprano but will bump it up to concert if necessary.
After pricing a few components my thought is that I might do 3 of these simultaneously, keeping the bodies identical but using different cones so I can compare them. If I go this route then my friend will get his pick, I'll keep one, and one may be up for grabs, we'll see. I don't expect to get much done until next spring at this point, mostly design and planning.
In the mean time, lots of uke playing with StrumMn!
Check http://strummn.shutterfly.com/ for dates/times and come join us!