I'll try to help you. First of all YBR Yellow Brick Road uses the same ATX 450w supply that all of our games since Pirates use and is replaceable off the shelf.
The first generation of WOZ had 5vdc light boards and used a modified ATX power supply PLUS a standard 40 and then later 60w switching power supply to run the lights - any switcher pretty much will do that job. To replace the modified ATX you have to modify an ATX power supply which is not the end of the world.
THEN came the UPS Unified Power Supply era. This board was an all in one and is in most WOZ games made prior to the introduction of the 2.0 lighting system. It is this power supply that is no longer available and no longer buildable due to obsolete components. The solution we have come up with and that is slowly being implemented out there is to substitute the NEXT generation power supply which in-house we call the Dr. Hung supply (named for the man that developed it for us based on the coming 2.0 light system and its needs). This is a more or less standard ATX with an extra module built onto the side of it (detachable) and debuted with The Hobbit. However, later WOZ games that have FACTORY installed 2.0 LED board systems - and there are more than you might think that were built this way - also come with a Dr. Hung supply installed at the factory. These are still in stock at the new factory. ALL Hobbits use them. This has become the replacement after the fact for the obsolete unified PS although it is not strictly plug n' play and needs a bit of information from the game so that it can be tweaked a bit (in some cases). This is a work in progress (retro fitting it for WOZ I mean; the power supply is rock solid).
DI represents a new start - boards all moved up into the head behind the monitor and the permanent shift to more or less standard ATX supplies for the future (Pirates / Wonka / GnR / Games 7 and 8, etc). The aforementioned YBR WOZ fits in here also.
Does that help?