To those who were talking about different configurations of power supply, from previous experience I was trying not to be too ambitious on my first attempt, and just wanted to get something working.
An external supply may be the only option for the slim G series units, or any of the disc players, where half the available space appears to be given over to the disc drive. That wasn't going to be the configuration of my first attempt, though, as its difficult to justify the extra time to something that I couldn't be sure was going to work.
An external supply is also a bit more complex. I guess I'd need multi-pin XLR conenctors for the power supply connections, BUT I'd like to keep the separate return lines for the 5v & +/-12v supplies, plus a separate ground, plus the sensor lines to compensate for the additional wiring and connectors. That makes for a complicated connector.
With an external supply, I could presumably use a single supply to drive multiple units - a player, a controller and an HD621, for example. I'd be tempted to use a single large transformer feeding individual rectification & regulation modules for each equipment. It would be difficult to swap units around, then, though.
Finally, I didn't change the orientation of the supply in my V2 as I have to strip it every time I remove the PSU, plus I fitted the R3 cover to the chassis, which closes the box (bar some ventilation slots). That will have to do.
Nick