Kamenoostrovski paloace will be fully restored in 2013 on purpose of the use for the guests of the town.
http://karpovka.net/2011/09/02/26640/
The first time I was in St Petersburg I stayed in a hostel on the sixth floor of an abandoned tower block in the south of the city. It cost $3 a night.....But the guy who owned that place claimed to be restoring the Kamenoostrovsky Palace as well! - I assume this was nothing more than a dream of his, though who knows what promises were made to whom back then! (it was 1993; he was a former government physicist who presumably had connections).