You can stream anything at any bitrate, but 2x 720p on 5 Mbps would be a very extreme case. That would be a third to a quarter the bitrate of a 20-year-old DVD, or 3.5 - 7% the bitrate of a Blu-ray disc. That's less than half the 'Extremely Low' preset of the Sorenson encoder, the lowest you can go without defining custom options.