Late last year, Magellan introduced their new Triton series of handheld GPS units, whose higher-end models let you download raster topographic maps to the unit from the commercially-available National Geographic Topo! series. Initial reaction to these units was very bad; you can see how bad by reading the Amazon.com reviews for these units:
Supposedly many of the initial problems with these units have now been fixed. And now there’s a free program on the GPS Tools website by Mikhail Sharonov called TritonRMP that lets you calibrate and convert any raster image, map or photo, to a Triton-compatible format. I don’t own a Triton, so I can’t try it out, but users on the Triton forum are reporting good results with many different kinds of raster images. And at less than $175 for the Model 400 Triton, this may be the cheapest way to get decent raster imagery on a handheld GPS.
If you own a Magellan GPS of any type, the entire GPS Tools website is worth a look. While there are lots of tools for map and data creation for Garmin handheld GPS units, there is far less support for Magellan units, and Mikhail’s website has more tools for the Magellan than I’ve seen anywhere else.