The full Senate vote on Roberts will be on Thursday. It is unlikely that W will name someone before the Roberts confirmation is sealed. I suspect that he will name someone after that but not at the swearing in ceremony, when the spotlight is on Roberts as it well should be.
I agree with that. President Bush has indicated that he is hopeful the Senate will perfrom its advise & consent function, and his comment was phrased in such a way that he does not take an up or down vote as a gimme.
I don't believe President Bush will make another SCOTUS nomination until the Roberts nomination is disposed of. And then, as you note, he's likely to wait a few days after that before making the name of his next SCOTUS nomination public.