User experience practitioner roles

I'm dealing with an interesting situation right now. I'm trying to create a list of user experience "roles" with short descriptions. I'm using "role" here in the usual sense - not a job description but a set of closely related tasks and responsibilities that tend to be performed by a single person. And of course a single person might handle multiple roles.

This has been done plenty of times before, and for the most part it's pretty straightforward. There's a "user researcher" related role, an "interaction designer" related role, and a "usability tester" related role.

But there are a couple places where things get tougher.

First, how does one describe a "UX architect" role in a way that distinguishes it from the other roles. Given that I'm a UX architect, you'd think this would be a piece of cake, but I'm struggling with it. I have plenty of anecdotes that describe what I do, but distilling it down into a short description or bullet points is eluding me.

Second, how do you distinguish between a UXer who does interaction design and a "developer" who does interaction design? Obviously there are plenty of technical architects who spend their time on design and not coding, but we also have non-architects with development backgrounds who spend all their time on low-level design and don't do any coding. Are these people "UXers"? As someone who thinks my undergraduate and graduate degrees did close to nothing to prepare me for my career in user experience, I don't think there's any reason why someone can't "convert" from a different domain to user experience. But I can't shake the feeling that there's something vaguely different about the roles that has nothing to do with ability.

I wonder if all professions are as imperfectly defined as our's, if you're looking at them from the inside?