mshilarious, two things.
> Stick with 2 or 3mA, and you should be OK.
No, you shouldn't. There are good microphones from AKG, Neumann, Schoeps, Shure, CAD, Earthworks and other manufacturers that won't run, or won't run correctly, within that limitation. If you're looking for a compromise, I'd propose 5.5 mA per mike. That will exclude some CAD and Earthworks models but it should cover all the rest.
At 7 mA you reach a break-even point--drawing more current than that means dropping so much voltage across the 6.8 kOhm phantom feed resistors that less power is actually available to the microphone, the more current it draws beyond that point. In my universe the manufacturers would be reasonable and stop there--but "I only work here."
The other point (I won't quote you back) is about the noise level of the phantom supply. This is largely an unwarranted concern, and the "specifications" being offered have little bearing on reality. It's admirable to build a quiet DC supply, and all other things being equal, I'd try to build a quiet supply also, just as a matter of personal pride. But the phantom powering method (as contrasted with "modulation lead" or "T" powering) is inherently immune to supply noise, because the circuit guarantees that it will occur in equal amounts on both signal lines at the same time. Thus any hash or ripple or other gunk in the phantom supply is a "common mode signal" and is suppressed just like any other common mode signal at the input to the preamp or recorder.
This is why professional audio uses balanced connections in the first place! For professional-quality studio microphones and preamps, common mode suppression can amount to 70 - 80 dB under good conditions. Even under bad conditions (e.g. long cable with unequal resistance in its two modulation leads) you'd probably still get 50 dB of common mode immunity. It's not that hard to build a phantom power supply in which the noise from the supply itself would be, say, 10 dB below the noise level of the microphone at all frequencies.
--best regards