Your real-life Pip Boys now come in two flavors - visually accurate, with few functions; or fully-featured with a different design.
You can actually purchase this sucker, which weighs in at more than a pound and measures 4.5 by 3.5 by 3 inches (a whopper, in other words). But the Zypad WR1100 does include a GPS receiver, electronic compass, biometric fingerprint sensors, and a position detector that switches the thing off automatically whenever your arm hangs down by your side.
It does not, however, pick up Galaxy News or Enclave Radio. So while the Zypad may not be good for your cosplay outing, in case of actual nuclear holocaust, it will help you navigate the wastelands. Provided the GPS satellites are still in orbit and functioning.