Bring back the xenon flash.

I worked in Sprint customer service and that can be bypassed...
Just call customer service and say you moved to another city, san francisco and give a valid address.
They will have to change your physical address in the system and make a CSA Swap (Call Service Area) and you'll can have the san francisco plans. (note: you'll have another number with a different local area of course, but since national long distance is covered in most of sprint plan... who cares)

After you have your new plan you can change your billing address in the sprint webpage or call customer service again and say you're in a bussiness trip or something... so they just change your billing address. That won't make your number change and your mail will drop in your "temporal" address.