I think there is lot of scope for new research on this subject and I suspect there folks who are already doing that. There are lots of undiscovered papers and notes tucked away in various libraries and archives...that is what Darlrymple stumbled upon when he wrote his new book.
Saul David's The Indian Mutiny is rather good too - But as always domestic historians are contesting what Dalrymple says without as much as giving the book a read.
