Hi i am female and bought a North Face Ion 20 backpack. My 11 inch Macbook Air fits very comfortable. It is extremely lightweight and comes with a rain cover.

I tried several North Face backpacks in store and this was the lightest of them all Jester,Isabella,Borealis,Recon,Hot Shot,Surge II and it also had a dedicated laptop compartment to fit my 11"MBA. My Macbook Air sits very comfortably as the laptop compartment fits up to 15". I really like this model, with it's handy waist pockets and lightweight material. Padding feels comfortable and i wouldn't vouch for it, but the 15" inch laptop compartment seems to be able to carry both 11" MBA and your Lenovo X220 (12.5").

In fact, my brother has a Lenovo X230 and i a 11" MacBook Air. If you want i can ask him to bring it to me so i can try to fit both in my TNF Ion 20 and see how it goes.
Here's my Ion 20 (got it 3 days ago) :




These are more dedicated laptop, larger capacity backpacks that may serve you well for your quick trips and to your business style depending on your capacity needs:
http://www.thenorthface.com/catalog/...ml?from=subCat
http://www.thenorthface.com/webapp/w...atalogId=10201
http://deuter.com/en_DE/backpack-det...=Giga%20Office

The Surge II has some serious dedicated laptop compartments and lacks a bungee cord if you don't like to bring this for business. Borealis is great if you don't have a problem with bungee cords and capacity should be ok with all your list. Deuter is a german brand that makes very high quality backpacks, my brother also has one of those packs and he likes it. I believe Deuter even makes more quality offerings than North Face, but i find TNF the most stylish. Those and my Ion are my picks for backpacks.