on the other hand if every share would be worth 5 BTC, then the company would be worth pretty much 2 000 000 BTC, which is 17 percent of bitcoins in circulation, that would be a lot, some could say too much
There is nothing to fear if a company's worth is greater than all the currency in circulation. "There was approximately $1.19 trillion in circulation as of June 5, 2013, of which $1.15 trillion was in Federal Reserve notes" according to the Federal Reserve:
http://www.federalreserve.gov/faqs/currency_12773.htm.
The most valuable American company is, I believe, Exxon Mobil with a current enterprise value of $413 billion.
Exxon alone is therefore worth 34.7% of all US dollars outstanding.
And the enterprise value of the Dow 30 (again only 30 companies) is far greater than the total number of US dollars out there.
There will only ever be 21 million bitcoins. There is no upper limit on the value human beings can create when they apply their minds and bodies to creative, productive endeavours. There is no direct correlation between a currency's supply and the value of an economy. (It is only government manipulated variations in supply of currency that can have an impact in causing distortions in economies and thereby create temporary and unsustainable activities in an economy, but that is beside the main point of this message.)
This can be a tricky concept - for example, if ASICMINER became worth
BTC22 million, would that be possible? The answer is still yes. Consider, the value of a share is the present value of its future dividends. If the utilization of bitcoin reached a level where there was a high velocity of bitcoins such that the worldwide annual gross transaction value exceeded
BTC10 billion, (roughly $1 trillion dollars at today's prices), then a .25% fee applied against that entire number would be worth
BTC25 million bitcoin alone per year. If Asicminer retained kits 25% share of mining, it would be able to pay an annual dividend of
BTC6 million and would only need to trade at 4 times its dividend price (a dividend yield of 25%!) to have a value in excess of all the bitcoins in circulation. I know we are very far away from having that volume of bitcoin transactions out there. This is more intended as an exercise to show how it is possible for there to be things out there "more valuable than all the money in the world", even in monetary terms. But it's also nice to dream of a day when there would be that kind of transaction volume on bitcoin.