When it just goes pear shaped

The diagram to the right is an approximation to a position I saw at the ANU Chess Club on Wednesday night. I'm pretty sure it isn't quite exact, but is close enough for the purposes of this post.
Clearly White is winning, with some sort of doom about to occur down the open h file. And indeed the obvious 1.Qh2 is the quickest way to end the game. Black replied by running the f rook across the back rank 1. ... Rfe8 (again this may not have been the actual move).
So White now has a choice of winning ideas, but here it began to go wrong. Spotting a brilliant finish to the game, White went for a Q and R sacrifice. 2.Qh8+ Bxh8 3.Rxh8+ Now if Black plays the obvious 3. ... Kxh8 it is all over after 4.Bxf6+ Kg8 5.Rh1 But Black chose the only other legal move in the position 3. ... Kg7! and White must have realised something was wrong. f6 is protected, and Rxh8 is on the cards so White charged on with 4. Rh7+ Only now did Black capture with 4. ... Kxh7 (4. ... Kg8/f8 still loses to 5.Bxf6). There followed 5.Bxf6 with the threat of Rh1+. But with the king on h7, rather than g8, Black had one way to escape, and he took it with 5. ... g5! To his horror White realised there was no longer a mate, and down a Q+R for Bishop, he resigned.
I wouldn't call 2.Qh8 an outright blunder btw As the defensive idea was a four moves down the track, and involved a couple of subtle defensive moves, it was more like a tragic miscalculation.