What seems particularly strange in some of the current discussions of Q is that, precisely at the moment when scholars far and wide are calling for the dismantling of long-standing conceptual walls between religious and cultural traditions of antiquity (for example, between Palestinian Judaism and Hellenistic Judaism, or between orthodoxy and heresy), some are portraying the Q community as walled off from the rest of early Christianity, even though such persons will claim that itinerant missionaries went out from (and presumably returend to) the Q community, traveling about Palestine and Syria! Surely the theology and life of the Q community had dimensions that are not reflected in the Q document itself. Since it narrates no fellowship meals, must we assume that the community had none? (p. 38).
Apparently Hultgren is working on a Romans commentary (though I cannot remember this source of this information).