I Need Your Surplus Hub Brakes and Hubs

I'm a middle school teacher. I have a long term project to put together an educational program using bicycles to talk about history, technology, gears, structures, and so on. For the "hands on" part of it, I thought students could take apart and put together some hub brakes (minus rim and spokes, and degreased and cleaned). The New Departure Model D is too complicated for this, but a brake like the CCM "37" is perfect. I realize this is an important part of a vintage bike, but perhaps there are newer versions of this brake, or worn out old ones (do they ever wear out?) that people have lying around doing nothing and wouldn't mind parting with. If you have an extra brake, one with pitted bearing cups, etc that you don't need, could you consider sending it to me? I will pay for the postage, and if you want a small sum for the hub too that would be ok. It does not have to be cleaned, but if you're going to mail it could you remove the rim and spokes? This is a project for my retirement which is still some years away but I am collecting stuff now. I will need at least a dozen. I will take front hubs too. -Brian R.