Dell has an extended battery for the Streak 5,so one could infer that the same will be provided for the 7".... and click the developers forum for the Streak 7.... it's already been rooted, instructions are given there.
Check out the Digital Digest review on Youtube... unbiased and positive.
Didn't read gizmodo's cus they are ridiculous... and got pissed at the Engadget review because they shoot things down over trivial items such as "veiwing angles" which IMHO aren't even a factor for me when deciding to buy a device.
I have the Streak 5 because I want a tablet with phone... I tried the Galaxy Tab... nice, but no 3G Tmo phone access and too many hurdles involved in getting the phone working...
If the Streak 7 comes out with Tmo 3G access, might consider it. But I have to say I LOVE the Streak 5... perfect blend of portability and function to me.