I have a garmin GPS unit currently gathering dust b/c I'm almost always on trails with a map. When I really wanted, though, was something similar to what you are talking about. Google "gps data logger". These are small GPS units for tracking data points that you can use later with other software or Google Maps. This is the kind of thing you might have one a keychain, use with a camera or make your rebellious teenager swallow so you can track them. There are a few that have basic displays.
It would probably be worthwhile to check what kind of GPS chips these have, though.
Edit: try this page. I don't know anything about Semsons but this one has a large number of units: