After a lot of research and experimentation, I think that I have come up with a design that meets most of my goals. I use the LM317 family (LM317, LM338, and LM337) for regulation of both voltage and current. This design allows analog control of both voltage and current setpoints, so that you can connect a MCU and a DAC if you want to, or you can just use a potentiometer. The modular design allows you to choose to not populate the current limiting regulator + associated op amp if you do not care about adjustable current limiting. Likewise, by bridging some resistors and leaving out others, you can change the same board into a negative regulator with the LM337.

I have a version currently working on my breadboard: you can set both voltage setpoint and max current using a MCU + DAC, and it keeps the output within those limits regardless of load. (The current limit is not yet programmed in, so I don't have actual valid numbers showing for the values; however I can change the DAC output and observe the limit changing, so I can tell that it is working. Getting real calibrated current limiting is the next step). I also have not yet tried it with the negative version (LM337), but will do so before ordering the board.

Testing has been going very well with this version. Line and load regulation are very clean at all tested loads (up to 3.5A).

I had to make some concessions from my original design goals:

• Full current adjustment limits are only available on lower amperage channels (I am arbitrarily limiting this to about 10V / 500mA, although there should be nothing keeping you from going up to about 1A as long as you change the software a bit, and possibly change some of the resistor values). Use a 1 ohm shunt resistor for this configuration.
• High amperage channels (5A, using the LM338) do not support adjustable current limiting. They still do have the short circuit protection built into the LM338, though. Use a 0.1 ohm shunt resistor for this configuration.

A schematic is included below. I would greatly appreciate any comments on this design.

I will try to post more details over the next few days as I do more testing.

Cheers