Via Jim Watts at Iconic Books, a story in The Art Newspaper notes that "the Egyptian government has made a formal request to borrow the Rosetta Stone from the British Museum" for a three-month period in 2012 to coincide with the opening of the Grand Egyptian Museum.
BM trustees are expected to weigh several major factors in their consideration of whether to allow the loan to go forward: first and foremost, preservations concerns. Secondly, "if the Rosetta Stone can be lent in view of its iconic importance. It is probably the single most-visited object in the BM’s entire collection, attracting even more visitors than the Parthenon [Elgin] Marbles. The Rosetta Stone has been at the museum since 1802, and has only left the building twice - when it was evacuated during World War I and when it was lent to the Louvre for one month in 1972."
Finally, there is some concern "over whether it would be prudent to lend to Cairo, because of possible pressure in Egypt to retain the stone or request its permanent return."
The paper adds: "In March, Dr. [Zahi] Hawass [head of Supreme Council of Antiquities] told The Art Newspaper that he intends to seek the loan of five key masterpieces from international museums. The others are the head of Nefertiti (Berlin Museums), the Dendera zodiac ceiling (Louvre), the bust of Hemiunu, builder of the Great Pyramid (Roemer and Pelizaeus Museum, Hildesheim, Germany), and the statue of Ankhaf, builder of the Khafre Pyramid (Museum of Fine Arts, Boston). 'I will give guarantees for their safe return,' he promised."