Yeah for some reason mapping providers are seemingly reluctant to release media card based maps for the BlackBerry. I could be cynical and say its to encourage more data use which makes the carriers happy but I'm sure that's not the reason.....
There is a demand for it and I know a few companies that are working on it but haven't tested how good they are yet (once I do and I'm out of NDA I will of course post it up here).
If you want to use the GPS for a digital compass I'm sure there must be a third party app somewhere that shows you your lat/long, bearing, speed, etc (if not there will be in the near future as a small part of some software we are working on
).