Speck, known for its cases, has introduced its first backpack — MightyPack ($80). The debut backpack for the company can hold up to a 15” MacBook, and there’s plenty of space for other accessories, including an iPad and iPhone. A vegan fur-lined “Tech Locker” pocket near the top of the bag has a hardshell for extra protection, and a hole inside the bag allows users to pass cables between compartments for charging purposes.…