Balkinization says: "Circuit court judges are bound by Supreme Court precedent, are also bound by the precedent of their circuit. So we don’t know much about how they’ll be when they’re unbound, when they grow comfortable in their Supreme Court robes. And advocates argue their clients’ positions, not their own, so we’ll never know if any of the statements he made as a lawyer were his own beliefs."
And so, almost everyone is a "stealth" candidate, except for a few hardcore book writers, law professors, bloggers, pundits, and lawyers whose careers are wrapped up in their causes - a group that might be collectively called, depending on your point of view, a bunch of kooks.
On this point, Beldar opines in response to this interesting post from Professor Barnett that "doing law is substantially harder, and ultimately more meaningful, than just writing, lecturing, and blogging about it." I don't know about harder or meaningful, but certainly different. It's not quite like the difference between writing about golf and making the PGA tour, but definitely not the same.
I suspect that people who think they are entitled to know what a nominee thinks about some particular case or issue or doctrine are missing the point that the people who create a paper trail on such matters are a limited and unusual group.