Disk Space Questions

Hi. I had a few questions about disk space. First of all, is there a way to see how much disk space I've sold? (I've been giving resellers the amt of disk space they paid for in their reseller privallages page and then let them own their own account, so I wanted something which can add all those up to show how much I've sold (not the amt which is currently being used))

Also, I wanted to see if there is currently or if there will be a way to see how much each reseller is using of their purchased space and bandwidth (them + their customers). I figure this would be a great tool for webhosts in possibly contacting the person to offer them an upgrade of account package if they are running low on space or bandwidth to sell to their customers. Thanks so much!