Lift to drag ratio of airliners
In quotable literature, I recommend „Aerodynamic Design of Transport Aircraft“ by Obert. In other useful stuff, there is a very useable (but not proven by Boeing) aerodynamic model of a 787 available on the Piano X website.

I‘d add that for any really useful analysis other than level flight, getting hold of a decent engine model giving maximum and minimum (net) thrust as well as fuel flows throughout the operating range will, in my experience, prove much harder than the aerodynamics...