I know, probably not historically accurate, but for what it's worth, the BJCP style guidelines do say "Hints of roasted malt may be present (sometimes perceived as a faint smoke character)," and that has me thinking. Rather than rely on roast malt and hope that some smokiness comes through, I'm thinking I'll add a little bit (~1% of the grist) of smoked malt. But which kind, is the question? (Peat is not listed as an option!)