I am looking at the Garmin eTrex 35t now. It is a touch screen, but it has a lot going for it. There is a bike mount for it, uses AA batteries, is waterproof (IPX7), runs the remote speed/cadence sensors, has a micro SD card slot, and can run other software/mapping (topo, lake, street). I am going to research this one a bit further. The open source maps may work with it like people have been doing with the bike units. From what I gather the gpx file format is fairly universal. I have been converting between kml (google earth) and gpx for a few years already. It looks like I would be able to do the same with the handheld eTrex.