Welcome back! I am a huge fan of the old metal stealth suits myself. I'm not a very experienced Tau commander, so I can't tell you with any certainty on how to expand your force. I usually just get whatever I think looks coolest and then try to make formations with what I have or buy the missing pieces I need to make them.
As far as the bitz your are referring to, there aren't any that are specifically those two. You could always custom make the parts or use another bit as it. I don't think anyone would question it as long as it wasn't a gun.