Landmarked districts

you have to go in front of the Landmark committee. if they let you, fat chance in hell, you can do it.

You can do what the guy on East 62nd did and leave your beloved a fresh building space.

I am pretty sure you can't build "whatever you want" anywhere, and somehow convincing LPC to let you tear down a building in a landmark district would be near impossible. Then you'd have to deal with the community board, etc etc etc...

It can be extremely difficult, but do-able, for some restricted version of 'whatever you want'. The zoning and use of the specific lot within the district can also make it easier: churches and schools have more latitude in their use. I've found community boards to be of limited use in opposing significant change, and LPC is not immune to pressures from other neighborhood organizations (which have often have overlapping memberships and directors) and the paid-for testimony of experts who will claim the design is 'appropriate' (I'm looking at you, Berkeley-Carroll School).

Ok, look what I found for instance:

http://streeteasy.com/nyc/building/44-mercer-street-new_york

They built it on top of a regular cast iron building. Also, the building does not even abide by local zoning rules, it is 7 stories in a zone where the FAR is supposed to be 5...

http://archive.citylaw.org/lpc/permit/2004/044161.pdf

FAR of 5 doesn't mean it has to be 5 stories. It means the square feet can be up to 5x the square feet of the lot. Seven stories sounds about right.

First, I'm not sure that Little Italy is landmarked - you need to go to the LPC website to figure that out. There's always the intriguing possibility of demolishing a building overnight (I believe Macklowe did it once) or slowly defacing a building and then there is nothing left to preserve. Not sure what the LPC can do in those instances if the ability to build new is worth more than penalties (I'm not even sure if the LPC can fine anyone).

In the case of 44 Mercer and any landmarked building, you can always add a glassy penthouse addition. Visibility from the street, what neighboring buildings have done, etc. all play a role in LPC approval

Some buildings which are landmarked have already been so substantially altered by the time of landmarking, that it is quite possible that the LPC would approve an all-new glass building.