After reading the recent Typical Patterns Everyone Should Know article by  GM Gserper regarding attacks along the h-file it seems pretty clear that one can obtain impressive attacks along this file.  It also made me think...is the king safe in the middle of the board?  As it seems that castling is either delayed (and done on the Queen side) or not done at all.  Are there games at the higher levels where GM's actually keep the king in the middle and how often is it successful?

Most of the time castling is a sound and wise option. You should usually castle unless you're castling into a pawn-storm or readymade attack.

There are certain openings which often feature the king in the middle. Various lines of the Sicilian (including the Najdorf that I play) often involve Black's king sheltering in the middle - usually because there isn't pawn cover on either side and there's a solid wall of pawns in the middle.