A piece on Salon by Sean McElwee, which suffers from an unfortunate headline (not his) and a bad last sentence, leads me to re-ask the title question. And the answer is, of course, yes. Richard Smalley, Nobel prizewinner in Chemistry for the discovery of fullerenes, was a creationist. I know he had serious problems with evolution because I discussed it with him on a visit he made here at Nebraska. It's also a matter of public record.
Henry Schaefer III probably one of the worlds top 5 living quantum chemists, and is another. he's laid out his problems with evolution quite articulately, and he's a fellow of the 'Intelligent design'-promoting Discovery Institute, which almost all evolutionary scientists consider a creationist Trojan Horse.
After an inflammatory letter I wrote to the local newspaper about the local Seventh Day Adventist college (I'm trying to be nicer, really!) I was invited by a physics professor there to present a lecture on the 'atheist view of the origin of life' to his 'Origins' course. He asked me to promise I wouldn't curse or blaspheme. After we'd gotten around that (apparently unintentional) piece of rudeness, I agreed to do it, as long as the title was changed to 'the scientific view of the origin of life'. I gave a lecture, it was well received, several students asked intelligent questions, and then we went to lunch.
I asked him how he reconciled his Adventism, which insists on the literal truth of the Bible, with what he knows of physics. He said he certainly doesn't reject radioactive dating, etc., but he's constrained to believe the Bible is true. He therefore believes the two are reconcilable, though he doesn't think we know how to do that yet. While I find that unsatisfactory, it's a great improvement over the usual idiotic creationist attempts to shoehorn science into a young-earth-creationist timeframe, slicing off all the toes in the process, or make ridiculous arguments the Second Law forbids evolution, or that there is evidence of intelligent design in cell structure or the human genome.
So can a scientist be a creationist? Of course. The origin of the universe, life or species has zero impact on the structure of organic molecules, quantum physics or, indeed, most of science. Sure, creationists compartmentalize, refusing to use the same evidentiary standards for origins questions that we do in other fields, but so do we all. For example, most of us act as if we are freely choosing entities even though we accept deterministic physics applies to our brains. (I think Dan Dennett has done a reasonable job reconciling the two, but it's still a pretty raw paradox.)
Moreover, I don't think we win by overstating our case, or exaggerating its strength. I'm doing NASA funded research right now on the origin of chirality in living organisms, and it's basically shooting down one current hypothesis, leaving us without any explanation whatsoever. We actually don't understand the origin of life, at all. I'm confident we will, and that the origin will be naturalistic. But that is definitely a gap in which a creationist can temporarily house his god. Good luck to him; it doesn't hurt science, unless he tries to pretend the immense amount of scientific knowledge we actually do have is in his favor.
(clean up and links to be added later; got to set some homework).