Yes, they're right, cobalt bits are the way to go.
We purchased one and used it for the first time today. Even with our regular 18v Black & Decker cordless drill it worked on a majority of the rivets.
On the rivets it didn't completely cut through, it weakened the heads enough that we were able to flake them off easily with the chisel without widening most of the holes. However, if you happen to slip with the drill - BAD NEWS! We made our first gouges into the vinyl cladding (?) today.
They weren't too noticeable - I hope. One other bad thing is that the drill does appear to make some of the holes bigger, just like the chisel. Is this because I'm a little off center when I'm drilling some of them? Will we have to buy bigger rivets to reinstall the skins?
This reminds me of a question someone else asked on another thread, but I don't think anyone answered: When the walls start looking like swiss cheese, can you just re-rivet into the old holes and hide how bad it looks? If there are any leftover holes from different placement of furnishings, etc., is there any kind of filler we can buy?