Official silence on such an annoying issue is unacceptable.
That said, it's clear that if Apple acknowledges the blank update screen bug, it will turn into another "Apple is becoming Microsoft" news story and the stock goes down another 10 bucks. Yes, they should be brave enough to address it publicly. But it's also understandable why they're acting this way, no doubt scrambling to fix it without wanting to call attention to their latest screw up.
None of the rebooting suggestions posted above worked for my iPad3.
But in the meantime, there is a workaround, at least for me:
Using the App Store app, select the Purchased tab instead of the Update tab. On my device at least, it shows my installed software. Those programs that need an update will say "Update" in the button to the right of the program. Those that are current will say "Open."
Just scroll down through the list and tap Update as you find them.
Admittedly annoying and clearly needs fixing. But if you have dozens of programs, rather than hundreds, it will get you updated until Apple fixes the bug.