I'd go with the cock bead, depending on your gaps' widths. Unless you make your own bead tool and round it by hand, the bead stock will need to be near 1/4" thick. At least I can't find a router bit to round over thinner stock.
You could lay in contrasting wood, as you suggested, and make a cock bead of the same wood. Might look pretty cool.
As an aside, I used cock beading on a dresser and applied it to the openings rather than the drawers. Worked well.
'The true soldier fights not because he hates what is in front of him, but because he loves what is behind him.' G. K. Chesterton
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