This is something I am still searching for too. I despise backpacks for IT equipment. As in my sig, I normally carry an X220 and my rMBP. Right now I am looking at the large Bolt by SFBags.com. I have their Cargo (which is a great gear bag for all of my various crap, like wiring kit, small tools, punch downs, toners and probes, etc) and a waxed canvas Muzetto. Neither are what I want for a 2 laptop bag.
I have also used a bunch of different Samsonite bags which I absolutely love, but again, nothing that really works well when I want to carry two small laptops.
When I get the Bolt I will do a review for it as a 2 laptop bag.