I don't have a case like that myself - my mac is of the same vintage but a macbook not a pro - but if you're interested, I've started a thread where I am trying to put together a list of all the manufacturers or brands or designers (Whatever) of sleeves and cases for macs (and other apple products). Maybe you can check those out if you still need something 🙂
(and if you contribute to the thread, that'd be great too!)