Hi,
Unfortunatly no. Fortunatly, I have in my drawer a quite large project aiming at doing just this. You define your UI via xml and if you want to have a button, you have an action to do that and it will only disappear if you explicitly delete it, not because you left the state you created it in.
It's still very alpha, pm me if you are interested, it has a lot in store, multiple ways binding between Fsm Variables and ui components properties, you can even all describe in xml and have a button fire a global or even local event to any fsm or a given fsm, all of this within your xml
you can show hide groups, parent components to anything you defined with an Id in your xml ( say you have a horyzontal layout view with id 'hello' you can parent y button to 'hello' and it will simply add it to this layout, so hard referencing or difficult pointers to maintains. It has a lot more as well, like in editor preview of the xml description file, etc etc.
I kind of left that project aside, because it's a beast, and because Unity is working on a better UI system, but since it's not coming any time soon, It might be good that I spend a bit more time on this to release a version to the community.
bye,
Jean