We really have a soft spot for all things multifunctional. And really, can you blame us? Travel, as exhilarating and exciting as it may be, comes with a few restrictions, most notably the amount of luggage you can take with you. So, packing smartly is of utmost importance. Collapsible water bottles? Sign us up.  Lightweight and foldable shoes that take up almost no suitcase space? Yes, please. Bags that do double, even triple, duty? Absolutely. After all, why bring a carry-on bag, a backpack for hiking, and a tote or a purse for dinner, when you can bring one that easily converts into all three? We are especially fond of backpacks and duffels that not only transform into other styles, but are expandable, too. We can all use some extra packing space after a week abroad when we spend half our budget on souvenirs and keepsakes, right? This is where that pair of shoulder straps that converts a duffel into a more comfortable backpack also comes in handy. Even high-end designers have endorsed this utilitarian trend by realizing that even their jet-set customers need pieces they can easily take from day to night. So whether you are looking for something more urban- and business-appropr...