I don't ever plan to write a story on this, but someone should because it's an interesting idea. I would read it. This would probably take place in a world not too dissimilar from ours, except that medical technology would have to be more advanced. Basically, It would be a story of a man who freakishly becomes the suspect of his own murder. How is this possible? Well it's somewhat unrealistic, but he would be the first person to have survived a brain/head transplant. (I believe they have actually done this in monkeys and dogs with the circulatory system, but not for anything else.. As disgusting as it may be). In the story, this would be an illegal and secret operation because the body receiving the transplant is essentially being murdered or euthanized, regardless of whether or not the brain being taken out is spared by some means (being placed in anther body). The man on trial (who has the brain of the other man) is therefore actually being charged as an accessory to the murder of the body he now inhabits.
In which case I will write anything you want, and I do mean anything... as long as the pay is good. I mean, how else do you interpret "I have a a great idea, you write it" without the usual "...and we'll split the profits."