I was trying to parent the 3d object (box) to the guiTexture when it disappeared. Yea to camera works. I agree, sure to get a workaround but this is what PM is for and it's something everyone can use.
For the most part, yes, using 3d objects will work, but isn't the issue with building out your UI so it's scalable for not just iOS? Not to mention the different resolutions of the devices.
I guess you can get screen width and height to know how big to scale up the 3d UI?
It just seems you can always have a workaround but something like this should just work.
I don't really agree with the way you express yourself in the part I put in bold, that things like this should just work. I'm not saying it would be a bad action to have, it would be, but seeing as there is an easy work around I feel that actions that does things not possible in PM yet is more important. It was a suggestion to help you out. You've made your request and I am sure Alex has put it on his todo list and will weigh the priorities of what needs to get done first. Also, something to keep in mind is that a 1.0 (or in this case we are now at 1.1) version of any software isn't going to be able to do everything.
In my own opinion, Unity's GUI system is very limited and outside of printing text I wouldn't really use it. But that's completely up to you of course. I would personally really love to see more custom actions for EzGUI. Cheap plugin for Unity that you can use to set up very fancy GUI systems. Of course right now you need to script to use it so actions to access those functions would be great IMO.
Anyway, you've made your voice heard, I gave you a work-around until Playmaker will have that custom action and it's up to you to decide where to go from here! Either wait for the action or try to work around it!