Well eventually I also got the canned "keep an eye on the press release page" from @TMobile.
Then I saw @askdes tweeted about 300k pre-registrations for the S5 so I attached the question to his tweet.
https://twitter.com/askdes/status/441626202109796352
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@SievertMike THIS JUST IN!#GalaxyS5 pre-registrations at@TMobile now over 300K! HUGE!#uncarrier#breakup#unleash
@askdes Will a Galaxy S5 with 32gb or 64gb internal storage be available? if not you can remove my pre-registration. Only 299k!!
I got a notification this morning that he favorited my tweet, so I don't know, I guess you could read it as a good sign. It's probably going to be as close to an answer as we'll get on the subject until they do push a press release which, looking at previous announcements, should be coming up soon if the S5 is really due to be released around or by April 11th as rumored.