Multisite- CSS sheet

I love multisite!!! Thank you WPMU!

I have only one quarrel. I have a theme on my super admin. I have child themes uploaded too and enabled over the network (genesis framework). However, each site doesn't have the ability to make changes to the css sheet/home.php/functions.php ?

I am shocked. Is there a way to upload child themes on the multisites so I can have different versions of the same themes?