The SURFN won't be practical from a consumer's point of view because as we all know too well, most airlines are charging for even first checked bag... and then everything after that. I'm pretty sure the average flier will forgo the ability to easily haul their other bags to save 5o bucks. The other two look functional and practical though. Albeit a little large..
That strolln looks downright dangerous, imagine it being fully laden by a muppet, all top heavy, then a careless or distracted parent takes hands off handle, rushing man late for departure brushes by, over goes suitcase "FACEPLANT" your kid needs reconstructive surgery or a coffin!!