No. Sifter supports due dates associated with milestones, or groups of issues, but our experience is that individual due dates for issues gets a bit too granular.
The underlying problem is that with due dates and priorities, the true priority of issues can become ambiguous. For example, is a critical issue with a due date a week from now more important than high priority issue due tomorrow? With Sifter, we try to keep things as focused as possible by avoiding this kind of ambiguity.
We've also found that the granularity of individual due dates can make things a bit messy as they frequently end up outdated. Moreover, we find that when an individual issue needs its own due date, it's because it's critical and due yesterday. In those cases, the due date is usually redundant with the priority.