well if my sleuthing skills are correct, this presentation (http://www.slideshare.net/PjotrAtVSTEP/ship-simulator-professional-20-introduction-1683290) shows on slide 5 that singapore is probably coming to Shipsim, and on the previous slide Dover and Calais are likely to be included in Ship Sim Extremes, especially as they've already been rendered in SSPro (in fact, Dover appears in the teaser trailer for SSE.)
We'll just have to wait and see.