I also want to be able to print and/or download the "Quantity On Hand" column on the "Build Assemblies" screen. I've contacted QB several times about adding that ability. I put in the request last Fall.
If more people ask for an improvement, I believe that increases the chances of QB making the change. I think you should also submit your request to QB. I believe in QuickBooks you just go to "Help" and there should be an option to submit feedback.