I so hope you can keep developing this. Right now I use the Trimble software (which is very good), but a single-pay program rather than a subscription model with certain features could easily compete. The key features: Use of GPS location (both internal GPS and external puck support) and the ability to download my GPX files without the desktop. I could take or leave the maps, but a tracking feature would be ideal. If you're familiar with the Geocaching software in the PPC world, I'd first shoot for a BeeLine GPS-type program rather than a Backcountry Navigator-type program.