Anyone who tries to manipulate Sorting Hat at age of 11 would automatically and deservingly be sent straight into Slytherin.
Do you think it is possible for the Sorting Hat to see through powerful mind control spells? Modified memories, obliviation, imperius, etc.
Better yet, polyjuice. Send some other kid in that looks like you and is willing to go along with your plan out of loyalty.
Just brainstorming here. It's quite possible that the Hat would yell out "Well, this guy is going to Hufflepuff but wedrifid is going to Ravenclaw!"
Which reminds me, the hat works by piggybacking of the intelligence of the wearer. So I would pick the dumbest Hufflepuff friend that I could find!
Update: This post has also been superseded - new comments belong in the latest thread.
The second thread has now also exceeded 500 comments, so after 42 chapters of MoR it's time for a new thread.
From the first thread: