hi deathwish. Are you looking for something on a 5 pin header so it can fit into a breadboard?
You mentioned that the suppliers from china make all these "modules" ( I think you mean populated and functioning PCB boards) but they don't make a case too. And thus they are strewn about your bench unprotected. I agree with this, I have several open boards like this and I hate it too. If it's worth putting into a case then I'll just make a case for it myself, either using something quick and dirty (i.e. altoids) or if I want a pro-look I'll buy a case.
For your PSU, if you had a PC board with DC-DC convertors on it, that gave you +5, +12, -12, and it had a 5 pin 0.1" header, are you plugging that into a breadboard? But you also mentioned shields, so that's a different use-case than a breadboard.
So, what's your use-case for your PSU with +5, +12 and -12, and what do you want it to look like ?