Old style Legacy non-lined computer bags work... or the nylon mens transatlantic line.
I have a 13" MacBook, so mine's a little smaller, but I rotate several bags as work/laptop bags. Thompson Hobo, Legacy Pocket Tote (the original "Brooklyn"), Hamptons Business tote with the legacy stripe laptop sleeve, and if the weather is bad - Denim Convertible Signature Stripe. I can actually fit my laptop in my large Maggie, but the weight worries me a little.
Good luck finding something that works for you!