cost of high end gut renovation

sorry, this is supposed to be in the renovation category

Depends on your definition of high-end. Sheetrock walls are one thing, venetian plaster over lath and a scratch coat is another. Parquet wood floor tile from Home Depot is one thing, 3" x 15" oak strips set in a herringbone pattern with a decorative contrasting border around the edge of the room is another. Both of the latter are high-end. The former are not. P.E. Guerin makes exceptional door hardware, much of which is made to order. Custom designs, of course, take longer.

If you're in the sort of building that contains lots of the latter examples, the renovation time could be anywhere from 1 year to 3, depending on how quickly the crew works ('high-end' does not usually equate to 'speedy'), and any restrictions the building has on when renovation work is permitted (some buildings have entire seasons when you cannot do work).