Asus has lately become the king of anime-style transforming electronics, with their Transformer tablet line and Padfone devices. It looks like Google is paying attention, at least when it comes to conceptual hardware. US patent 8,649,821, granted to Google in February of this year, describes a laptop with a built-in and detachable cell phone, with the two working in tandem for various functions. While Android and Chromebooks aren't specifically mentioned in the patent documentation, it's easy to assume they were on the engineers' minds, since it was filed in September of 2012.
The basic idea is that the laptop can borrow the cell phone's wireless connection for on-the-go Internet access, as well as use the removable handset as a speaker and microphone for VOIP calls and other obvious functions. In turn, the phone can use the laptop's larger speaker as an amplifier when docked (or I suppose just let the user answer the call in a laptop mode, not unlike the desktop integration currently available from Google Hangouts). The phone could presumably use the laptop's larger battery as an external reserve. The patent drawings definitely show a device that slides into a specifically-made slot, not just a simple USB tether, which can do pretty much all of these things right now.
The idea echoes Motorola's Lapdock designs seen on the original Atrix and other phones, but almost in reverse: the documentation seems to indicate that the phone is only being used where a full laptop would be impractical, and that the laptop portion of the hardware can work independently of the phone. (That's not possible with the tablet/keyboard shells on the various Padfones.) As such, this hardware combination would combine two full and independent devices, not just a primary device and accessories. That would cost a pretty penny, and for frugal consumers, buying a pair of specially-made devices that might not work with the next generation of either one is a daunting prospect.
Still, as Android and Chrome grow closer this sort of hardware crossover becomes more likely, and more attractive. If Google could create a system whereby the power, connection, files, apps, and settings of all the separate pieces work together, it could be very compelling indeed. Keep in mind that this is a patent, not a prototype; while it does indicate that someone at Google is at least thinking about a laptop-smartphone combo device, it doesn't mean one is anywhere close to being created.