The latest rumour that I had heard was that two of the 2009 specials are to be filmed in the USA and will feature a “big name” American companion. Now with the other rumour that suggests that two of the specials have not be scheduled yet that these two episodes may form a two-part story.
The other rumour mentioned with these american episodes are that these are going to be the 10th Doctor’s final episodes now after the stunt they pulled with the regeneration that never was in Journey’s End, I am taking this rumour with a very large pinch of salt.
Now one of the specials is being broadcast at Easter and the other at Christmas means that these episodes could take place at any time before it, or even afterwards if these are to be the finale episodes of the tenth Doctor. Perhaps these will play on New Years Eve and New Years Day leading into the fifth series which will start a few months later.
I am assuming that these two episodes are the ones that are being written by Russell T Davies soley with the two co-written ones being the Easter special and the Xmas special. I would imagine that all of the specials will feature a big name guest star as the companion and by the end of the specials we will be left with a Doctor with no companions who will meet his new companion in the first episode of the 5th Moffatt penned series.