Error Connecting Nexus 7 to Ubuntu 12.10
Jelly Bean devices do not use USB Mass Storage to mount themselves on PCs. They use the more secure MTP method, and Ubuntu does not natively support MTP. 

The method you have linked to is the only official way to do what you want.

I own a Nexus 7, but I am using a custom ROM, and as such, USB Mass Storage is hacked into my build. However, I believe on the stock ROM, if you check in Storage and you press Menu, you should have an option to set the USB connection type, and there is a Picture Transfer mode. It won't let you see all of the files on your Nexus, but it will allow you to copy and it shouldn't need any extra help inside Ubuntu. 

For an extremely detailed explanation on MTP and why it exists, and why on the stock ROM you will never be able to use it as a flash drive, I highly recommend you check this StackExchange question:

How can I use my Galaxy Nexus as an external USB storage drive?