At factory.lego.com you can download program to work with Legos to make custom creations, which eventually you can buy just those blocks to make. I've downloaded the program and can run it from my usb key, but it always makes a folder in "My Documents" as the default place to save your models. I manually go to the folders on my usb key to save it.
I was just wondering if anyone else has tried to make this a portable app.
I've emailed the folks at Lego to ask if the program is open-source, and if it can be modified to change the default save location, but there hasn't been a reply yet.