Hello, this is quite an undertaking with making your own drum. Plan what you want before you buy. Remember to measure twice before you do any cutting/marking and have fun with this. If you end up getting frustrated put it down and come back with a fresh perspective.
Keller makes nice shells for drums... and they would be 100% maple. You can buy parts from online from places like Drummaker.com - Your Complete Source for Custom Drum Parts & Supplies
which is where I bought the parts for my snare. Over the last few years I have purchased two snare shells from them and both came through shipping fine. I had the bearing edges cut by drummaker and did the rest myself. If you want to check out my snare sound I posted a song here not to long ago.
How exactly do you plan to do the top? Will it be like a regular snare or are you going to add some form of a conga top? Do you have an idea for the depth?
I see two ways to attack
this. One way is to build the thing yourself. The other is to modify an existing conga (or mini conga) into a snare. Snares have wires… you can either add a bottom head with a snare system… or cut the snare wires in half and install a clamp inside the shell that will press the wires into the top head. Either way will work and will give you different sounds.
Skins are easy to come by… musiciansfriend or any local drum store will carry replacement heads.
As far as cymbals go… well if you are going to be using your hands then I recommend that you get a thin cymbal. There are some out there “designed” for hand percussionists… though you can get the same from a thin cymbal. I would go to a guitar center or local drum shop and start hammering away at some cymbals. It will give you an idea of what is out there and what you might be looking for. Gongs will be there as well.