For any on the fence about an additional battery, I just ordered the Verizon 2150 battery from their site. There is a sale running cutting the price by 30%. So instead of $59.99, got it for $41.99. Healthy saving. Yes, when I use it the Seidio case won't work, but since I have the wifi tether set up for the iPad now, I'd like the extra juice. I'll also drop a note to Seidio mentioning adding another case.
This includes overnight shipping for orders put in before 4:30 local time. Not a bad savings. If you can give up the case for now, might wanna jump on this. Will add a hair more size to the phone, but doesn't look like it will extend the back much more than what it is with the Innocase now.