Yeah I remember making 64bit builds a while back, so I guess it was possible. I guess it was Irrklang that was the thorn. Are you free to create new branches? If so, create a branch with the changes and I'll review it and if all checks out, it'll take over as the new solution file.
Sometimes you might want it to say 'Package...' with 3 dots to indicate a function w/ a popup dialog, in that case there's nothing you can do.
PluginManager.IDE.CurrentGame.RootPath
Sure, add it in!