Okay, so no one cares and no one uses LJ anymore, but I wanted to go ahead and get my theory about the BBC Sherlock down before too much leaks out. So, you know, I can decide how delusional or prophetic I might have been.
Okay, so the ball that Sherlock was playing with in the morgue had nothing to do with faking anything. I know that a lot of theories had him using it to stop his pulse, but he didn't need to, because he had Molly and the homeless network.
Nearly everyone on the ground was planted. Molly found a body which may or may not have looked anything like Sherlock, and she delivered it (planted it) on the ground - or maybe even by throwing it out a higher floor. Sherlock did, indeed, jump off the roof, but he had a relatively soft landing - not in a laundry truck, because it was too far out. Instead, he had his homeless network use some sort of easily removeable pad. The smaller building blocked John and the sniper's view, which was one of the keys to success. The other, of course, was the bicyclist.
Sherlock was always curious, so of course he experimented with the drug from Baskerville - he knew the chemical compositions or had a bit of it at 221B. So, the bicyclist that knocked John down was also the delivery system for the drug. After being dosed with it, John saw his worst fears come true. It didn't matter that the body wasn't Sherlock - he had seen him jump, so he feared (or rather knew) his BFF was dead. Also, the downtime gave Sherlock time to hide and his helpers time to hide all evidence of deception. The body went inside, and it was obvious to everyone that it was a lost cause, so the body would have returned to the morgue. It was an obvious suicide, so there would have been no need for an autopsy.
Of course, the how did he do it isn't nearly as interesting as the thought of how will everyone react when Sherlock returns. But, I guess we have a few months yet before we'll figure out either!