Discrete Sigma/Delta DAC

For purely educational reasons (for now), I'm interested in building a discrete Sigma/Delta DAC. I'm not interested in anything high quality/audiophile or in something cheap, I would just like to understand how they behave in practice and play around with them. But, it seems nobody else is interested in this as I can't even find schematics of thought experiments and there are definitely no kits either...

I can't imagine that nobody else is interested in such an experiment. Is it perhaps too hard to handle the high frequencies in a controlled way on a breadboard/DIY PCB? Are the distances between DIY-able components simply too large?
 
You can do the digital processing with an FPGA, a DSP or a general-purpose CPU; they are all Turing complete, so as long as they are fast enough and have enough memory, it doesn't matter much in principle.

Talking about Turing completeness, I see you are from the city where both Charles Babbage and Alan Turing studied and taught.