The MSM7xxx / MSM7xxxA chips FULLY support USB 2.0 in host mode - there are developers working on the driver ports as we speak, since the full chip specifications have been released in the wild (making this process turbo charged). This means that we will see the needed USB host drivers ported quite soon allowing us to utilize external USB cards on our MSM7xxx(A) phones running Linux.
That means I'll be able to actually use this setup of mine soon:
Secondly, how much juice do you think internal cards actually take in phones that are capable of injecting?? (i.e. acx chipsets).
Third, even using USB host mode on HTC's and the Freerunner with an rt73 card (WUSB54GC), I've never seen more than ~80mAh used MAX. For using the Alfa, yes -- you need to either buy or build a small power injector.