Its been discussed a pile of times, and there is like one I think. Let me search too.
EDIT: Here's one find, so yes, there is. Not easy to do, but I guess you can't have your cake and eat it too?
http://www.blackberryforums.com/gps-...highlight=card
EDIT 2: Another, not free, but you didn't ask for free either.
http://www.blackberryforums.com/gps-...thout-ota.html