I've recently read that around 100 passengers camp in the Stansted Airport departures hall every night, and that the number can go up to 500 in summer months! Not surprising when the cheapest flights depart between 5am and 8am, and even the most grotty airport hotel costs $100/night.
For some mysterious
reason, most aiports don't want passengers to sleep on their premises, which is why they design those really uncomofortable benches with armrests. But people do it anyway .
So I suggest a dormitory attached to the main departures hall in budget airline destinations such as Stansted. It is simply a large room with dimmed lights and sound proofing, covered in floor mats (like the ones in gyms), with enough floorspace for 500 pax and attached lavatory. You pay a fixed entry fee of $5 per night to spread you sleeping bag on the floor. For an extra $3 you can hire a folding bed.
I know that this idea is semi-baked in Amsterdam Schiphol and Singapore Changi airports, where "rest areas" offer comfy seats to tired passengers. Still, they are not meant for sleeping and you probably get kicked off by security if you try to use them overnight.