How Many Bitcoins Are Missing? Recently my HDD went, losing all of my data. I make backups frequently and luckily only lost 0.02BTC. I tried everything to recover them, but no luck. As I stated it was small amount that wasn't a much for me to pull my hair out. Just bang my head against the wall. And miss out on a day of coffee. 

But this got me thinking. Is there a way to find out how many bitcoins in the world are missing? 

I'm guessing that about 6000 transactions after all of the bitcoins have been mined, someone may be able to develop some sort of spider, bot or scrapper of some sort that will index the blockchain and make an educated guess by looking at the transactions.

And if that is so wouldn't it be possible to also determine the Bitcoins that are missing and remake or counterfeit the missing bitcoins?

I know Bitcoin uses SHA encryption. But with good computing power, the knowledge of none being made again. Couldn't something like rainbow tables be created to forge the missing bitcoins?
One cannot distinguish between saved and lost coins, because it is only possible to prove ownership of a private key, but impossible to prove that a private key is lost. I.e. nobody can tell the difference between whether I just haven't moved my coins for five years or I lost the key.

Coins cannot be counterfeited. 

Coins can only be spend by having access to the private key. Rediscovering a private key, though, is extremely unlikely and due to the amount of computation required most likely not profitable.