Both install /usr/bin/GrabWeather, d'oh!
Let's see, I could move gkrellweather's copy to something like: /usr/libexec/gkrellweather/GrabWeather I think that works for me. Done, and in the tree for gkrellweather-2.0.7-r2 Also updated all other gkrellweather and bbweather ebuilds to block eachother.