Hi Staci,
This problem still exists in the SF Bay Area on AT&T, as I just tested it. Kind of amazing that this anomaly hasn't been addressed by Eloqua yet.
There is no Eloqua work around in place. A possible solution might be to create a 'smartpage' in which all instances that you want to use a blindform are actually directed to a blank placeholder page with JS on it that takes custom querystring parameters and then executes the blindform submit from that page (pass the form name, Campaign ID, etc. via querystring). That might work and circumvent whatever redirect blockers that AT&T have purposefully/unknowingly have in place.
Best of luck on solving this one. If you do find a solution please share.
Thanks,
Kevin~