I think you need to meet the little rascal and see what comes to mind.
And why would you change your mind if you waited to see if they got another batch of rats into the store soon?
Ever check out Craigslist for pets? Go under "community" and then "pets." Might find someone who's trying to find a home for some they can't keep any longer. Just an idea.
I guess with their lifespan, you want to get them as babies. Did you see that in the other video I posted?