"Why would anyone drop one of these into a typical build where you might only have 1000 mA to play with on the +12v rail..." is what I said. Not that there's 1A present in draw per se, but typical cases, on average, tend to have about that on the +12 V rail.
But my argument still stands. Go back, and you'll notice that I mention that these have inrush current issues. This means that for a fraction of a second on power-up, the AIRA and 1M modules draw more than their given rating. So when running, sure, a couple of AIRAs pull 900 mA, just as rated. But during that inrush, the current draw is significantly MORE. Now, add that momentary overage to any other draws and/or inrush issues other modules may have, and you might only have about 1 second to use your build before the P/S pops. Not very useful. So my suggestion still is that, if these things have their own cases and power supplies, use them. It frees up space for modules that don't have that convenience...and also for modules that don't suck current that hard and aren't that huge. Case in point: the Roland AIRA Bitrazer. This fits in 21 hp, draws 450 mA on the +12V rail, and consists of a bitcrusher and a VCF and goes for $300 (albeit not now, since it's discontinued). Now, compare that with a high-end Eurorack bitcrusher + timbral modifier; we're going to use the Harvestman's Malgorithm mkII.
With the Malgorithm mkII, you pay $31 more. But it fits in 10 hp and instead of a filter on the output (filters are pretty ubiquitous in modular builds anyway) it provides a digital waveshaper for timbral changes, in four stages. The sample reduction can also work in a "foldover" mode which causes "...a foldover of input frequencies exceeding one-half of the sampling frequency (the Nyquist limit). This sounds like a strange combination of filtering and ring modulation, with bidirectional foldover (forward from zero Hertz) occurring at extreme settings." And last but certainly not least, this more-elaborate and smaller bitcrusher's current draws come in at 140 mA on the +12, 20 mA on the -12.
And this gets back to my other point, that Roland jumped in on Eurorack before figuring out how to Eurorack. The AIRA modules were something of an embarassment for them, because they built something that didn't fit the accepted format. They had odd panel sizes, which were not as common when the AIRAs came out, they had that beastly current draw (which indicates some pretty inefficient design; note that the Malgorithm mkII is just as much, if not more, a digital module as is the Bitrazer), and people didn't adopt them because of some of the "surprises" such as the inrush issue, etc. You'll notice that, after that fiasco, when it came time to start doing the 500 series...they turned to Malekko to design and build these for Roland, which is about as clear of a "we screwed up!" admission as you're apt to get out of Roland. Seriously, just leave these stompboxes-posing-as-Eurorack-modules in their own housings, leave the 1M in its own housing where it should go or, better still, rackmount it by a main patchbay where you can throw a lot of different signals at it, and use the Eurorack cab space for modules that get what modular synthesis does right.
