Ive been sent word that we will have a two part story set in Egypt for series 6, possibly to be set during the 1923 opening of Pharoah Tutankhamun's tomb, with apparent talks of the crew going abroad to film in a desert.
How true this is remains to be seen, and of course it would come down to having the right story and budgetary allowances, but if true could be quite an interesting story, especially with the supposed 'curse' surrounding the excavation.
The person who sent me this is usually spot on with his spoilers so although I adivise you to treat it as speculation for the time being, it might just be something that we will be seeing in the new series. They have filmed overseas in the past after all.
Is this something you would be happy to see in the show?