As far as I’m aware, Python cannot be obfuscated.
@piac, could your work on the GhPython add-on compiler be of use here? Otherwise, you could port your plugin to C# and distribute it as a RHP.
On the other hand, if you’ll allow me to get a little bit philosophical, I’d urge you to consider whether it really matters if other people see your code. It all depends on whether you’re focussed on selling yourself or your software, I guess. What are you most worried about?
Edit: Just saw that you were referring to a Rhino plugin, not a Grasshopper one!