I'm not sure about borderlands but thanks to the new update, you can use a usb drive as an xbox 360 memory unit (leading to be able to plug it into your computer and mod stuff).
Try this link :
http://www.se7ensins.com/forums/topic/191163-tutorial-usb-hdd-xplorer/
This is still beta and not completely ready but you can still try it. I succesfully modded an mw2 save game with this.
The USB drive update essentially allows any USB drive to be configured into a XBOX360 save device. Therefore it can be considered to be the little stepbrother of a memorycard, which you can also mod stuff from.
As long as you have a profile and saves from games on the USB drive and you are able to access them using some sort of program like Xplorer (http://www.se7ensins...sb-hdd-xplorer/) then you are good to go.
Honestly I think this allows the entire community to have the ability to mod simple things like saves now...which is good. Silly Microsoft