This is one of those chicken and egg problems. You are a nerd working on a team and you think that you’d all do well if there was someone responsible for the architecture (or design or builds or tests or…). In fact, you think that you are the perfect candidate. There isn’t a job opening. Nobody has announced the need. What do you do?
Should you talk to you boss and suggest that you starting doing it? What if she says that she can see that such a role might be needed but that you don’t have any experience? What if she says that your teammate Max would be better at the job and calls him into her office?
As you might guess I think that the best thing to do is to starting doing the job on the side. It will probably mean extra work. It will probably mean needing to convince co-workers that your ideas are worth it. However, the best way to show that you can do something and that its needed is to do it. Be careful not to be sneaky and be sure that you aren’t stepping on anyone’s toes too hard. Unless you work in a toxic environment your efforts will be appreciated and rewarded even if you aren’t successful in changing you role.