While it's possible for lots of different EM radiating sources to coincide and produce unusual peaks of energy, that would be extremely difficult to categorise in any useful way other than by observation. My head hurts with the idea of creating even a crude mathematical model of an aircraft full of bored punters playing with their gadgets. I've seen how researchers model office conditions for WLAN design, and even when you're limiting the radios to one design doing one job on one band, it's devilishly difficult to get useful answers - at one point they started to put sacks of saline solution in the chairs to model absorption by bodies - and the speed at which technology changes means you can't spend years trying all these ideas.
But that doesn't mean it's not possible to get useful results. Ideally, the aviation and ICT industries would work together to create and run a testing regime that models real life as closely as possible.