There are extensive references to this in the 'Koil Olugu'. I remember reading Sujatha expressing doubts on the '12000' number for reasons I dont remember now.
Koil Olugu also goes into detail on the travels of the urchavar (I believe called 'Azhagiya manavalar') during the 60 years of exile in Tirupati and other temples. There is also a theory that the idol brought back to Srirangam was a replica of the original and original one is still hidden in a temple unknown to others.
You know, when I saw that still of Kamal with the idol of Azhagiya Manavalar in 'Dasavatharam', I took interest and when I heard that Kamal is also playing a 12th century vaishnavite in the movie, I realized and am pretty sure that it is the story of 'Azhagiya Manavalar's travels during the sack of Sri Rangam. Most probably, Sujatha put him upto it...
Malik Kafur's attack on Srirangam, the valiant attempt by the priests, the urchavar's journey, the idol being kept in Tirupathi and later in Melkote, Veera Ballala's attempt to revive Hinduism, his tragic ending in the Kannanur(Samayapuram) war, Kumara Kampanna's defeat of the muslims and finally the urchavar's return to Srirangam are all covered in the books 'Thiruvarangan Ula' and 'Madura Vijayam' by Sri Venugopalan(aka Pushpa Thangadurai).
The novel says that when the temple finally re-opened there were two sets of idols brought to the temple and both are being worshipped.
Even today one can find the Ranga Mandapam in Tirupathi. A notice board says that the Srirangam deity was housed there for sometime during the Muslim invasion.
All I could find was the urchavar was moved out. Will chk with Koil Olugu. mm..interesting piece abt kirumi kanda Cholan.But then does it clash with the '12th century vaishnavite'? Thought Mr.Kirumi was in the 10th century? But we are speculating here..anyway, should be an interesting one..
-Hi some of the early leaks of the story indicated story starts in chidambaram. even today i met one of the actors who plays a role in the movie. he's so old that its going to be his last movie perhaps. i should have asked him.