When’s a mattress not just a mattress? (This isn’t a setup for a cheesy pun, we swear.) With so many direct-to-consumer startups out there, it’s becoming more and more essential that new brands offer more than just the promise of a good night’s sleep. With everything from hypoallergenic benefits to full-bedroom outfitting, these are the companies thinking outside the (UPS-delivered, surprisingly compact) mattress box. Now to make a decision…