I'm not sure about writing a front end in Go, there's not a lot in terms of UI frameworks and Iron.io front end (HUD) is still in Rails so I can't really say much about it.
Sorry, deployment was probably the wrong word - I was not so worried about getting the files up there (like you I have a simple home-grown solution for that), but more how you were handling process management, swapping out processes etc.
Perhaps with Go this is less of an issue because startup time for new processes is minimal, and you can simply kill one process, start another and not really miss any requests (unlike say Rails with startup times of 10 seconds or so for instances)? Did you find this wasn't a big issue in practice and something very simple works for you?
I'm currently playing with go but if considering it for client use would have to be sure that things like this were not an issue. Are you using any off the shelf tools for process management/load balancing or is it something that you have built yourself? Did you run into any problems?