I completely agree with you cory. The only places where I see 7075 as having a noticeable impact on performance is on gears and shafts where strength is very important and there is a constant load working on the shaft. Adding flanges to the sideplates will increases the stiffness much more than just switching to 7075 aluminum. Also 7075 is very expensive stuff.
If anyone wants to see flanges, look at my last drivetrain I posted
http://www.chiefdelphi.com/media/photos/32013?