I've found Mic Modeler incredibly useful as a replacement for double-tracking vocals and instruments. Try this:
Instead of wasting a dozen or more takes on a particularly difficult vocal passage trying to get two usable tracks for a doubled vocal, pick the single best take. Clone it and pan each clone 15-20% L/R, then apply the Mic Modeler to one side. For extra reinforcement of the "multiple vocal" effect, apply two distinctively different, but short decaying reverbs to the channels. Perfectly timed, extra-dense vocal with none of the timing and pitch problems associated with multiple physical takes.