Well, I have 4 transformers (3 Stern SAM/Whitestar and 1 WPC-95)(technically, I have more, but those are random ones like Bally home edition, etc). I also have
1) Sys11 power board
2) 2x Stern Power I/O boards(whitestar)
So, ultimately, the easy way to do this to wait for a P-ROC(they are on backorder). It can control the Power I/O board out of the box, I don't need to rearrange any of the plugs and I have all of my power needs met. Add a PC controller and I'm done with the controller/power side.
A second idea is to use the sys11 power board and a sys11 aux power board. I would have to do some plug adaptation for this, but I would have the same voltages, and no need for a controller board to actually drive the Power I/O board(since it also drives the solenoids/lamps, you need to have a board pulsing the lamp matrix every 50ms or it goes into reset). This would likely be driven from an APC/PC combo.
I could build an Arduino based board to control the Power I/O board and control it from an APC. I'm actively working on this solution, but it does seem to be overkill. On the plus side, I end up with the ability to drive 48 solenoids(I think) and 144 lamps in a matrix. It's the same APC/PC combo from above.
Now, in terms of switching power supplies, it was my initial approach. I didn't like it for a couple of reasons:
1) Need a separate PS for each voltage(50v, 28v, 12v, 5v for most systems to cover flippers, low power solenoids, RGB lamps and logic)
2) I would still need to condition the power for most of those voltages(one capacitor board per 50v, 28v and 12v at minimum)
3) I would need to distribute the wall voltage to each of those supplies. I'm less inclined to mess with that side of things. I like what the team doing The Last Starfighter is doing, but I don't have the skills to pull that off solo yet.
A switching PS solution isn't going to save me much, if any, real estate. And it will come with its own challenges. But this is exactly the conversation I was hoping to happen.
I would love to have a power supply packaged up for homebrew systems.